(In reply to L.S.S. from comment #9)
> Just tested... it seems if I connect to the monitor directly the problem
> doesn't occur.
> 
> Guess the KVM does play a part in this. However, I still need the KVM as
> I've four PCs connected to this monitor.
> 
> It's not a major issue as switching it back and forth would put the system
> back to the correct resolution, and it currently doesn't have any serious
> impacts. Just that I'm wondering why this problem is only happening on AMD
> video cards and not on nVidia video cards.

Possibly different behavior in the the hw or hw settings on what is considered
a short vs. long pulse for DP.