Yes, I was just documenting that for the developer on that. It's the message card (the blue part) that's not updating; the navigation and page URL are changing as they should. Very hard to replicate on demand, but we're still working on it.
This is intentional in that the entire page doesn't update while nexting through posts, which is much faster. We need to find what is making the message card stick and not update with the rest of the variable content.
So it is impossible to find out what the old alias was.
Is that true?
You won't find any clues in the member's profile. That's always been the case. But it usually isn't "impossible" to discover the old alias, though you may have to read a fair number of posts and replies to find one in which another member addresses him by his old handle.