Okay newest version with the auto bump off (which indeed seems to be the cause).
New Disp 2px autobump off:
Old Disp 2px autobump off:
I assume it is a bug then?
Another thing I notice is that new version has considerably more shading "artifacts". And those artifacts gets worse the further you go from camera. Is this expected? Should I just decrease px size to like 1px and forget? Or there's something wrong too?