Moderators and room owners have the ability to remove stars from chat messages. Currently this leaves no trace on the chat message that it was ever starred or who destarred it. Compare that to pinned messages, where you can see in the chat message history who pinned it.
Destarring a post is not a normal user action, but a moderation action and should in my opinion be logged in the message history.
This is not an important issue, if it's easy to add it would be nice to have it, but it's not an essential feature by any means.