Hey boss, triggered by the 3U name ?
For now the problem is gone, removed flash and installed the current version from Synaptic.
(Naugty me tested from testing and came running back to the standard Synaptic version)
And no I was NOT running flash from testing before the problems started.
System is fully updated.
A quick check on some testboxes, including one 3U, also some inverted colors
Problem videocards are different nVidia flavors, where the Synaptic version from now has no color problems.
The nouveau driver is also in the PCLinuxOS repo, so check it out