Other Configuration Manager-related features and issues
Client cache management and peer cache are both application/package centric; i.e., individual files are not tracked or managed outside of their package/application except for software updates. Clients inform the site that they have content available using state messages.
If content is removed from a client's cache, it should send a state message to the site to tell it that the content is no longer hosted on the client. I've never tested this though so will ask the devs to validate.