I’m not sure if this is a known issue, because I couldn’t find a similar post on the forums here but I might’ve overlooked something.
If you change the ownership of a post from user A to user B, and then you change the username of user A to C, and you view the post edit history of that post you changed ownership, it’ll still show "Ownership transferred from A to B" even though the image/username after that message is correct.
Example:
original username was mozzarella and it was later changed to mozzarella2 after the ownership of that post was changed.