Designer Issue with Ignition v. 8.0

Hi all,
after a long time experience with 7.9.x Ignition versions, I’m now switching to verion 8.0 - second project now.
I’m experiencing the following stability issue with Designer (Vision project): all of a sudden - no reason found - the Designer starts flickering, getting unusable - it’s even difficult to select an object on an open display. Only Designer close/re-open let me go on working. Moreover when this happens, the background color of the page I’m working on changes to a dark gray automatically.
I’ve monitored SQL Server queries with MS SQL Server Profiler - my pages has up to three custom properties whose datatype is DataSet, updated just at page start or with a refresh button which executes system.db.refresh - but found nothing strange. Also Windows Tasks are show nothing abnormal.

Any idea? Any performance key value I can look at to debug this issue?

Thanks in advance, regards

Ignition version is 8.0.12 (b2020042115)
OS: MS Windows 10 Pro (10.0.18362 build 18362)