user hacking an admin account

Hi.

I'm an admin on a forum. Last night we had one user post under another user's (an admin no less) username. Very quickly the post disappeared but not before we had noticed. The poster then said they had had error messages etc and then connection issues when other users also realised the post was written by the 'wrong' user. We believe that the admin's account was hacked somehow by the user but we would like to rule out a technical glitch. Is it possible that a technical glitch could have resulted in one user's post appearing as though another user had typed it? Is there any way at all that this could have happened? We think it's a long shot but would like to be sure.

Thank you for your help.

General>Forum>Security
Administration actions
Check if the admin deleted a thread?

No the admin hasn't deleted a thread.

We believe a normal user has logged in as an admin somehow. She then posted about her own children, revealing it can't have been the admin posting but the normal user and then the post was deleted but we had seen it. So it appears that this user has somehow gained access to an admin account. Before we accuse/ban the user we need to make certain it isn't a technical glitch. Does that make sense?

Thank you, I see what you mean now and the problem is solved.