PRESS Ctrl + F5 and see if that works, it looks fine here
Nope, that doesn't make a difference either.
And it would have surprised me if it had, since I already tried clearing everything using this panel:
Never mind, I wasn't even aware of this pre function before you mentioned it.
(and I am not going to test further, it's quite annoying loosing preferences for other websites and having to confirm all sorts of preferences again)