diff --git a/src/wp-includes/class-wp-theme-json.php b/src/wp-includes/class-wp-theme-json.php
index c20960bd0f9cc..8697ad5fc5a13 100644
--- a/src/wp-includes/class-wp-theme-json.php
+++ b/src/wp-includes/class-wp-theme-json.php
@@ -1330,6 +1330,14 @@ protected static function sanitize( $input, $valid_block_names, $valid_element_n
 
 		$schema_styles_blocks   = array();
 		$schema_settings_blocks = array();
+		$breakpoint_states      = array_keys( $responsive_media_queries );
+
+		$common_block_settings = static::VALID_SETTINGS;
+		// `viewport` and `blockVisibility` are global-only settings and cannot be set per block for now.
+		unset(
+			$common_block_settings['viewport'],
+			$common_block_settings['blockVisibility']
+		);
 
 		/*
 		 * Generate a schema for blocks.
@@ -1340,21 +1348,27 @@ protected static function sanitize( $input, $valid_block_names, $valid_element_n
 		 *
 		 * As each variation needs both a `blocks` schema and responsive `blocks` schemas
 		 * for further nested inner `blocks`, the overall schema is generated in multiple passes.
+		 *
+		 * All blocks start with the same style schema. Build that common schema
+		 * once, then add block-specific pseudo and custom states below.
 		 */
+		$responsive_block_schema             = $styles_non_top_level;
+		$responsive_block_schema['elements'] = $schema_styles_elements;
+
+		$common_block_schema             = $styles_non_top_level;
+		$common_block_schema['elements'] = $schema_styles_elements;
+
+		foreach ( $breakpoint_states as $breakpoint_state ) {
+			$common_block_schema[ $breakpoint_state ] = $responsive_block_schema;
+		}
+
 		foreach ( $valid_block_names as $block ) {
-			$schema_settings_blocks[ $block ] = static::VALID_SETTINGS;
-			// `viewport` and `blockVisibility` are global-only settings and cannot be set per block for now.
-			unset( $schema_settings_blocks[ $block ]['viewport'] );
-			unset( $schema_settings_blocks[ $block ]['blockVisibility'] );
-			$schema_styles_blocks[ $block ]             = $styles_non_top_level;
-			$schema_styles_blocks[ $block ]['elements'] = $schema_styles_elements;
-
-			// Add responsive breakpoint states for all blocks.
-			foreach ( array_keys( $responsive_media_queries ) as $breakpoint_state ) {
-				$schema_styles_blocks[ $block ][ $breakpoint_state ]             = $styles_non_top_level;
-				$schema_styles_blocks[ $block ][ $breakpoint_state ]['elements'] = $schema_styles_elements;
+			$schema_settings_blocks[ $block ] = $common_block_settings;
+			$schema_styles_blocks[ $block ]   = $common_block_schema;
 
-				if ( isset( static::VALID_BLOCK_PSEUDO_SELECTORS[ $block ] ) ) {
+			// Add responsive pseudo-selectors only to blocks that support them.
+			if ( isset( static::VALID_BLOCK_PSEUDO_SELECTORS[ $block ] ) ) {
+				foreach ( $breakpoint_states as $breakpoint_state ) {
 					foreach ( static::VALID_BLOCK_PSEUDO_SELECTORS[ $block ] as $pseudo_selector ) {
 						$schema_styles_blocks[ $block ][ $breakpoint_state ][ $pseudo_selector ] = $styles_non_top_level;
 					}
diff --git a/tests/phpunit/tests/theme/wpThemeJson.php b/tests/phpunit/tests/theme/wpThemeJson.php
index c2cda7bb158d0..407489e6d26f2 100644
--- a/tests/phpunit/tests/theme/wpThemeJson.php
+++ b/tests/phpunit/tests/theme/wpThemeJson.php
@@ -8242,6 +8242,94 @@ public function test_blocks_without_pseudo_support_ignore_pseudo_selectors() {
 		$this->assertStringNotContainsString( 'p:hover{', $theme_json->get_stylesheet( array( 'styles' ) ) );
 	}
 
+	/**
+	 * Tests that responsive pseudo-states are kept only for supported blocks.
+	 *
+	 * @covers WP_Theme_JSON::sanitize
+	 *
+	 * @ticket 66003
+	 */
+	public function test_sanitize_keeps_responsive_pseudo_states_on_supported_blocks_only() {
+		$theme_json = new WP_Theme_JSON(
+			array(
+				'version' => WP_Theme_JSON::LATEST_SCHEMA,
+				'styles'  => array(
+					'blocks' => array(
+						'core/button'          => array(
+							'@mobile' => array(
+								':hover' => array(
+									'color' => array(
+										'text' => 'blue',
+									),
+								),
+							),
+						),
+						'core/paragraph'       => array(
+							'color'   => array(
+								'text' => 'black',
+							),
+							'@mobile' => array(
+								'color'  => array(
+									'text' => 'green',
+								),
+								':hover' => array(
+									'color' => array(
+										'text' => 'red',
+									),
+								),
+							),
+						),
+						'core/navigation-link' => array(
+							'-current' => array(
+								'color' => array(
+									'text' => 'purple',
+								),
+							),
+						),
+					),
+				),
+			)
+		);
+
+		$actual = $theme_json->get_raw_data();
+
+		$expected = array(
+			'version' => WP_Theme_JSON::LATEST_SCHEMA,
+			'styles'  => array(
+				'blocks' => array(
+					'core/button'          => array(
+						'@mobile' => array(
+							':hover' => array(
+								'color' => array(
+									'text' => 'blue',
+								),
+							),
+						),
+					),
+					'core/paragraph'       => array(
+						'color'   => array(
+							'text' => 'black',
+						),
+						'@mobile' => array(
+							'color' => array(
+								'text' => 'green',
+							),
+						),
+					),
+					'core/navigation-link' => array(
+						'-current' => array(
+							'color' => array(
+								'text' => 'purple',
+							),
+						),
+					),
+				),
+			),
+		);
+
+		$this->assertEqualSetsWithIndex( $expected, $actual );
+	}
+
 	/**
 	 * Test that block pseudo selectors work with elements within blocks.
 	 */