The behaviors haven’t changed.
CCleaner has never been able to clean files that are open in any apps, or by the system.
What has changed is that previously it would only tell you about browsers being open.
(Note that originally it did tell you, until hundreds of posts like this one made the developers stop telling you. With CCleaner7 they started telling again when some app and system files can’t be cleaned because they are open - that is all that changed about it).