I realized that sometimes the highways aren't visible on my machine.
With all this 'settings-changing' because of the 'growing menu' and 'framedrops' issue i suddenly realized, that the highways were visible, which they weren't at first after updating.
Maybe has something to do with the oculus-settings, sadly i wasn't able to reproduce it constantly to clarify what's triggering this issue.
I changed settings as ASW and Supersampling back and forth, restarted oculus service a few times - sometimes the highways are there, sometimes not. Took screenshots to show:
Will try to isolate the behavior to a specific setting this evening if possible.