8.6 Dual Monitor issue on rotated screen – 3030LT devices

Hello,

last week we did an update from v8.5_020 to 8.6_013.
We have a couple users with dual monitors, of which the second monitor is rotated for 90 degrees to the right.

Since the update tot 8.6, we have colored stripes on the rotated monitor.
If we rotate it back to normal position, the stripes are gone.

I have done a firmware downgrade to 8.5 and the problem was solved, so the issue is definitily caused by v8.6 (we both tested v8.6_013 and _019).

Any ideas??

kind regards
Peter