Outlines dissappear

Hi,
I have an issue with Rhino 6 display.
Whenever there is an model with more than 200-300 elements (mostly blocks) elements (the outlines) disappear when zooming in.
Full view:

Zoom:

More zoom and part disappears:

When selected it is “visible” again:

and shaded mode it is no problem at all…

graphic card is NVIDIA GeForce GTX 1070/PCIe/SSE2 with current driver updated today…

Hello - if you can, please send a file in this state to tech@mcneel.com. Please include a link back to this topic in your comments.

-Pascal