diff --git a/src/wp-includes/block-supports/elements.php b/src/wp-includes/block-supports/elements.php
index 54b96aa1dc064..41fd62eaa5ff7 100644
--- a/src/wp-includes/block-supports/elements.php
+++ b/src/wp-includes/block-supports/elements.php
@@ -16,7 +16,8 @@
  * @return string The unique class name.
  */
 function wp_get_elements_class_name( $block ) {
-	return 'wp-elements-' . md5( serialize( $block ) );
+	$hash = md5( serialize( $block ) );
+	return wp_unique_prefixed_id( 'wp-elements-' . $hash );
 }
 
 /**
diff --git a/tests/phpunit/tests/block-supports/wpRenderElementsSupport.php b/tests/phpunit/tests/block-supports/wpRenderElementsSupport.php
index 007ba8312e495..831189b6af6fc 100644
--- a/tests/phpunit/tests/block-supports/wpRenderElementsSupport.php
+++ b/tests/phpunit/tests/block-supports/wpRenderElementsSupport.php
@@ -159,6 +159,74 @@ public function test_elements_block_support_class_with_invalid_elements_prefix()
 		);
 	}
 
+	/**
+	 * Tests that duplicate blocks get distinct elements class names
+	 * on their rendered markup to avoid CSS cascade conflicts.
+	 *
+	 * @ticket 65435
+	 *
+	 * @covers ::wp_get_elements_class_name
+	 */
+	public function test_elements_block_support_class_with_duplicate_blocks() {
+		$this->test_block_name = 'test/element-block-supports';
+
+		register_block_type(
+			$this->test_block_name,
+			array(
+				'api_version' => 3,
+				'attributes'  => array(
+					'style' => array(
+						'type' => 'object',
+					),
+				),
+				'supports'    => array(
+					'color' => array(
+						'link' => true,
+					),
+				),
+			)
+		);
+
+		$block = array(
+			'blockName' => $this->test_block_name,
+			'attrs'     => array(
+				'style' => array(
+					'elements' => array(
+						'link' => array(
+							'color' => array(
+								'text' => 'var:preset|color|vivid-red',
+							),
+						),
+					),
+				),
+			),
+		);
+
+		$block_markup = '<p>Hello <a href="http://www.wordpress.org/">WordPress</a>!</p>';
+		$block_one    = wp_render_elements_support_styles( $block );
+		$block_two    = wp_render_elements_support_styles( $block );
+		$markup_one   = wp_render_elements_class_name( $block_markup, $block_one );
+		$markup_two   = wp_render_elements_class_name( $block_markup, $block_two );
+
+		$this->assertMatchesRegularExpression(
+			'/^<p class="wp-elements-[a-f0-9]{32}[0-9]+">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+			$markup_one,
+			'First block should have wp-elements class applied'
+		);
+		$this->assertMatchesRegularExpression(
+			'/^<p class="wp-elements-[a-f0-9]{32}[0-9]+">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+			$markup_two,
+			'Second block should also have wp-elements class applied'
+		);
+
+		// Extract class names and verify they are different.
+		preg_match( '/wp-elements-([a-f0-9]{32}[0-9]+)/', $markup_one, $match_one );
+		preg_match( '/wp-elements-([a-f0-9]{32}[0-9]+)/', $markup_two, $match_two );
+		$this->assertNotEmpty( $match_one, 'First block class name should be extractable' );
+		$this->assertNotEmpty( $match_two, 'Second block class name should be extractable' );
+		$this->assertNotSame( $match_one[1], $match_two[1], 'Class names for identical blocks should be unique' );
+	}
+
 	/**
 	 * Data provider.
 	 *
@@ -238,7 +306,7 @@ public function data_elements_block_support_class() {
 					'button' => array( 'color' => $color_styles ),
 				),
 				'block_markup'    => '<p>Hello <a href="http://www.wordpress.org/">WordPress</a>!</p>',
-				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}[0-9]+">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
 			),
 			'link element styles apply class to wrapper'   => array(
 				'color_settings'  => array( 'link' => true ),
@@ -246,7 +314,7 @@ public function data_elements_block_support_class() {
 					'link' => array( 'color' => $color_styles ),
 				),
 				'block_markup'    => '<p>Hello <a href="http://www.wordpress.org/">WordPress</a>!</p>',
-				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}[0-9]+">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
 			),
 			'heading element styles apply class to wrapper' => array(
 				'color_settings'  => array( 'heading' => true ),
@@ -254,7 +322,7 @@ public function data_elements_block_support_class() {
 					'heading' => array( 'color' => $color_styles ),
 				),
 				'block_markup'    => '<p>Hello <a href="http://www.wordpress.org/">WordPress</a>!</p>',
-				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}[0-9]+">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
 			),
 			'element styles apply class to wrapper when it has other classes' => array(
 				'color_settings'  => array( 'link' => true ),
@@ -262,7 +330,7 @@ public function data_elements_block_support_class() {
 					'link' => array( 'color' => $color_styles ),
 				),
 				'block_markup'    => '<p class="has-dark-gray-background-color has-background">Hello <a href="http://www.wordpress.org/">WordPress</a>!</p>',
-				'expected_markup' => '/^<p class="has-dark-gray-background-color has-background wp-elements-[a-f0-9]{32}">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+				'expected_markup' => '/^<p class="has-dark-gray-background-color has-background wp-elements-[a-f0-9]{32}[0-9]+">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
 			),
 			'element styles apply class to wrapper when it has other attributes' => array(
 				'color_settings'  => array( 'link' => true ),
@@ -270,7 +338,7 @@ public function data_elements_block_support_class() {
 					'link' => array( 'color' => $color_styles ),
 				),
 				'block_markup'    => '<p id="anchor">Hello <a href="http://www.wordpress.org/">WordPress</a>!</p>',
-				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}" id="anchor">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
+				'expected_markup' => '/^<p class="wp-elements-[a-f0-9]{32}[0-9]+" id="anchor">Hello <a href="http:\/\/www.wordpress.org\/">WordPress<\/a>!<\/p>$/',
 			),
 		);
 	}
diff --git a/tests/phpunit/tests/block-supports/wpRenderElementsSupportStyles.php b/tests/phpunit/tests/block-supports/wpRenderElementsSupportStyles.php
index 16ed26fc9c7bc..7707afee962fa 100644
--- a/tests/phpunit/tests/block-supports/wpRenderElementsSupportStyles.php
+++ b/tests/phpunit/tests/block-supports/wpRenderElementsSupportStyles.php
@@ -68,6 +68,71 @@ public function test_elements_block_support_styles( $color_settings, $elements_s
 		);
 	}
 
+	/**
+	 * Tests that identical blocks with different elements styles
+	 * generate distinct class names to avoid CSS cascade conflicts.
+	 *
+	 * @ticket 65435
+	 *
+	 * @covers ::wp_get_elements_class_name
+	 */
+	public function test_elements_block_support_styles_with_duplicate_blocks() {
+		$this->test_block_name = 'test/element-block-supports';
+
+		register_block_type(
+			$this->test_block_name,
+			array(
+				'api_version' => 3,
+				'attributes'  => array(
+					'style' => array(
+						'type' => 'object',
+					),
+				),
+				'supports'    => array(
+					'color' => array(
+						'link' => true,
+					),
+				),
+			)
+		);
+
+		$block = array(
+			'blockName' => $this->test_block_name,
+			'attrs'     => array(
+				'style' => array(
+					'elements' => array(
+						'link' => array(
+							'color' => array(
+								'text' => 'blue',
+							),
+						),
+					),
+				),
+			),
+		);
+
+		// Process two identical blocks with the same elements styles.
+		wp_render_elements_support_styles( $block );
+		wp_render_elements_support_styles( $block );
+		$actual_stylesheet = wp_style_engine_get_stylesheet_from_context( 'block-supports', array( 'prettify' => false ) );
+
+		// Both rules should be present with distinct class names.
+		$this->assertMatchesRegularExpression(
+			'/\.wp-elements-[a-f0-9]{32}[0-9]+ a:where\(:not\(\.wp-element-button\)\)\{color:blue;\}/',
+			$actual_stylesheet,
+			'First block element style should be present'
+		);
+		$this->assertMatchesRegularExpression(
+			'/\.wp-elements-[a-f0-9]{32}[0-9]+ a:where\(:not\(\.wp-element-button\)\)\{color:blue;\}/',
+			$actual_stylesheet,
+			'Second block element style should also be present'
+		);
+		// Count the number of distinct class names to confirm uniqueness.
+		preg_match_all( '/\.wp-elements-([a-f0-9]{32}[0-9]+)/', $actual_stylesheet, $matches );
+		$unique_classes = array_unique( $matches[1] );
+		$this->assertCount( 2, $unique_classes, 'Both blocks should produce distinct class names' );
+	}
+
 	/**
 	 * Data provider.
 	 *
@@ -127,7 +192,7 @@ public function data_elements_block_support_styles() {
 				'elements_styles' => array(
 					'button' => array( 'color' => $color_styles ),
 				),
-				'expected_styles' => '/^.wp-elements-[a-f0-9]{32} .wp-element-button, .wp-elements-[a-f0-9]{32} .wp-block-button__link' . $color_css_rules . '$/',
+				'expected_styles' => '/^.wp-elements-[a-f0-9]{32}[0-9]+ .wp-element-button, .wp-elements-[a-f0-9]{32}[0-9]+ .wp-block-button__link' . $color_css_rules . '$/',
 			),
 			'link element styles are applied'            => array(
 				'color_settings'  => array( 'link' => true ),
@@ -139,15 +204,15 @@ public function data_elements_block_support_styles() {
 						),
 					),
 				),
-				'expected_styles' => '/^.wp-elements-[a-f0-9]{32} a:where\(:not\(.wp-element-button\)\)' . $color_css_rules .
-					'.wp-elements-[a-f0-9]{32} a:where\(:not\(.wp-element-button\)\):hover' . $color_css_rules . '$/',
+				'expected_styles' => '/^.wp-elements-[a-f0-9]{32}[0-9]+ a:where\(:not\(.wp-element-button\)\)' . $color_css_rules .
+					'.wp-elements-[a-f0-9]{32}[0-9]+ a:where\(:not\(.wp-element-button\)\):hover' . $color_css_rules . '$/',
 			),
 			'generic heading element styles are applied' => array(
 				'color_settings'  => array( 'heading' => true ),
 				'elements_styles' => array(
 					'heading' => array( 'color' => $color_styles ),
 				),
-				'expected_styles' => '/^.wp-elements-[a-f0-9]{32} h1, .wp-elements-[a-f0-9]{32} h2, .wp-elements-[a-f0-9]{32} h3, .wp-elements-[a-f0-9]{32} h4, .wp-elements-[a-f0-9]{32} h5, .wp-elements-[a-f0-9]{32} h6' . $color_css_rules . '$/',
+				'expected_styles' => '/^.wp-elements-[a-f0-9]{32}[0-9]+ h1, .wp-elements-[a-f0-9]{32}[0-9]+ h2, .wp-elements-[a-f0-9]{32}[0-9]+ h3, .wp-elements-[a-f0-9]{32}[0-9]+ h4, .wp-elements-[a-f0-9]{32}[0-9]+ h5, .wp-elements-[a-f0-9]{32}[0-9]+ h6' . $color_css_rules . '$/',
 			),
 			'individual heading element styles are applied' => array(
 				'color_settings'  => array( 'heading' => true ),
@@ -159,12 +224,12 @@ public function data_elements_block_support_styles() {
 					'h5' => array( 'color' => $color_styles ),
 					'h6' => array( 'color' => $color_styles ),
 				),
-				'expected_styles' => '/^.wp-elements-[a-f0-9]{32} h1' . $color_css_rules .
-					'.wp-elements-[a-f0-9]{32} h2' . $color_css_rules .
-					'.wp-elements-[a-f0-9]{32} h3' . $color_css_rules .
-					'.wp-elements-[a-f0-9]{32} h4' . $color_css_rules .
-					'.wp-elements-[a-f0-9]{32} h5' . $color_css_rules .
-					'.wp-elements-[a-f0-9]{32} h6' . $color_css_rules . '$/',
+				'expected_styles' => '/^.wp-elements-[a-f0-9]{32}[0-9]+ h1' . $color_css_rules .
+					'.wp-elements-[a-f0-9]{32}[0-9]+ h2' . $color_css_rules .
+					'.wp-elements-[a-f0-9]{32}[0-9]+ h3' . $color_css_rules .
+					'.wp-elements-[a-f0-9]{32}[0-9]+ h4' . $color_css_rules .
+					'.wp-elements-[a-f0-9]{32}[0-9]+ h5' . $color_css_rules .
+					'.wp-elements-[a-f0-9]{32}[0-9]+ h6' . $color_css_rules . '$/',
 			),
 		);
 	}