Either the clock of bugzilla.redhat.com is going terrible wrong or this server is located in a special timezone (-0524 or so). Because I assume the first case, I suggest to use something like ntpd to synchronize the clock with the rest of the world... ;)
The problem is still there; Bugzilla appears to be about 5 minutes behind at the moment.
Fixed now. Syncing automatically with internal RH clock server.