diff --git a/packages/blocks/src/api/test/registration.js b/packages/blocks/src/api/test/registration.js
index ee12ad19159881..cc339e59d27053 100644
--- a/packages/blocks/src/api/test/registration.js
+++ b/packages/blocks/src/api/test/registration.js
@@ -1706,7 +1706,7 @@ describe( 'blocks', () => {
 
 		it( 'should correctly merge properties when bootstrap happens after registration', () => {
 			// Register source in the client.
-			const clientProperties = {
+			const clientOnlyProperties = {
 				getValues: () => 'values',
 				setValues: () => 'new values',
 				getPlaceholder: () => 'placeholder',
@@ -1715,7 +1715,8 @@ describe( 'blocks', () => {
 			registerBlockBindingsSource( {
 				name: 'core/custom-source',
 				label: 'Client Label',
-				...clientProperties,
+				usesContext: [ 'postId', 'postType' ],
+				...clientOnlyProperties,
 			} );
 
 			// Bootstrap source from the server.
@@ -1724,14 +1725,17 @@ describe( 'blocks', () => {
 			).addBootstrappedBlockBindingsSource( {
 				name: 'core/custom-source',
 				label: 'Server Label',
-				usesContext: [ 'postId' ],
+				usesContext: [ 'postId', 'serverContext' ],
 			} );
 
 			// Check that the bootstrap values prevail and the client properties are still there.
 			expect( getBlockBindingsSource( 'core/custom-source' ) ).toEqual( {
+				// Should use the server label.
 				label: 'Server Label',
-				usesContext: [ 'postId' ],
-				...clientProperties,
+				// Should merge usesContext from server and client.
+				usesContext: [ 'postId', 'postType', 'serverContext' ],
+				// Should keep client properties.
+				...clientOnlyProperties,
 			} );
 
 			unregisterBlockBindingsSource( 'core/custom-source' );
diff --git a/packages/blocks/src/store/reducer.js b/packages/blocks/src/store/reducer.js
index 74d03c20b2f987..048c2196899fc4 100644
--- a/packages/blocks/src/store/reducer.js
+++ b/packages/blocks/src/store/reducer.js
@@ -372,19 +372,19 @@ export function collections( state = {}, action ) {
 }
 
 export function blockBindingsSources( state = {}, action ) {
+	// Merge usesContext with existing values, potentially defined in the server registration.
+	let mergedUsesContext = [
+		...( state[ action.name ]?.usesContext || [] ),
+		...( action.usesContext || [] ),
+	];
+	// Remove duplicates.
+	mergedUsesContext =
+		mergedUsesContext.length > 0
+			? [ ...new Set( mergedUsesContext ) ]
+			: undefined;
+
 	switch ( action.type ) {
 		case 'ADD_BLOCK_BINDINGS_SOURCE':
-			// Merge usesContext with existing values, potentially defined in the server registration.
-			let mergedUsesContext = [
-				...( state[ action.name ]?.usesContext || [] ),
-				...( action.usesContext || [] ),
-			];
-			// Remove duplicates.
-			mergedUsesContext =
-				mergedUsesContext.length > 0
-					? [ ...new Set( mergedUsesContext ) ]
-					: undefined;
-
 			return {
 				...state,
 				[ action.name ]: {
@@ -407,7 +407,7 @@ export function blockBindingsSources( state = {}, action ) {
 					 */
 					...state[ action.name ],
 					label: action.label,
-					usesContext: action.usesContext,
+					usesContext: mergedUsesContext,
 				},
 			};
 		case 'REMOVE_BLOCK_BINDINGS_SOURCE':