since macOS 15.5 and iOS 18.5 bridged matter devices have isBridged set to false and the respective bridge device has an empty uniqueIdentifiersForBridgedAccessories list. before these updates both were set as expected. i also noticed that the bridged matter devices include all endpoints for all bridged devices. not only the ones for themselves.

MTRAttributeIDType is giving 'unknown cluster' results for every combination of cluster and accessory. for the same clusters MTRClusterNameForID gives the expected result.