clear mentionme name cache?

[DrXotick]

I'm not sure if cache is the issue, but we have a user who is not showing up as the correct color for their user group. It appears its using the users old group for color. Other members of that group are showing up fine. 

My best guess is that its cached his previous group (though he has been in the new group for quite awhile) 

Any ideas?

[DrXotick]

Still need help on this. The user is in only one group and is showing up as another group's color when mentioned. In other parts of the board he shows up fine (Last poster, thread starter etc...). It's only when mentioned that he shows up incorrectly.

I have checked in admin and is not part of any other groups. What possible reason could this be? mentionme cache is the only thing I can think of....