Qt Creator 4.12's Find Usages is finding usages of the symbol in other copies of the project

I use Qt Creator with Git worktrees to have several copies of the same project in active development at the same time. From Qt Creator's perspective, each worktree is its own project (with its own Qt Creator session), so I expect each Qt Creator project to have absolutely no knowledge of the others. There are no symlinks between the directories and there are no build system reference between the worktrees (like include or link paths). This all worked completely fine up until recently.

Now when I do Find Usages in one project it will suggest all the usages in the other worktrees as well as this one. This can be quiet dangerous as more than once I have have accidentally followed that usage and ended up editing a file on the wrong branch.

Git worktree doesn't seem to be the cause of the issue as I was able to reproduce the problem with multiple copies of a tiny test repo.

Has any sort of cross-project code model caching been introduce in a recent version?