Latitude E7250, external monitor flickering black.

Me and 2 co-workers got new computers, E7250.

Together with the E-Port Plus II docking station. (PR02X)

Problem is that one of the external monitors keeps flickering to black, as if loss of signal after a while.

Docking out and in again solves it, or removing the DVI-cable and putting it in again.

I run 3 external monitors + internal.

Co-workers runs 3 external only.

Same on all, one of the external monitors flickers.

I have the latest BIOS, latest driver for GPU and Chipset.
This does not help.

Any suggestions?