The more I investigated this error, the more confused I got. It’s to the point where I don’t even think I could give an accurate reproduction procedure.
All I know and all I want to share with people that search for this error message is that restarting Julia fixed the issue. This is the same solution that worked for a similar question.
Sorry, this is going to be very difficult if you cannot provide a reproducer.
I don’t need help. I only made this post to suggest to people facing similar issues to try restarting Julia.
If someone figures out what causes this (I suspect some Revise edge case, but I really shouldn’t speculate like that), then they should feel free to comment, but no need.