Screen flashing black after panning in AutoCAD 2019

[Michiel Roos1709158798]

We are building a new PoC for an Autocad 2019 deployment. AutoCAD works however we are having problems with the entire screen flashing/flickering black during certain operatings in AutoCAD. This is easily reproducible in my session when panning the drawing (hold middle mouse button and drag). After a few moments a black screen flashes black. The Workspace Receiver Bar on top of the session is still visible and does not flash black. One thing I noticed is that the first flash is different: if you have resized the AutoCAD window, it shows the previous size of the window. The same works for other windows or content. If I load a site in Edge and the navigate to a different site in Edge, the first flash will briefly show an Edge window showing the first site I visited. One thing I've noticed is that the drawing in AutoCAD looks like it's in itself a Windows application. 

 

So far we've looked at DPI settings since there is a lot of information on this, but changing the client or serverside settings doesn't make a difference. Setup is VDA 1906.0.1.1 with  NVidia M60 GPU with GRID M60-2Q profile and 425.31 drivers running on Citrix Hypervisor 8.0, the OS is Win10 1809. Graphics policies active are:

 

Visual quality Always Lossless 
Allow visually lossless compression. Enabled 
Use hardware encoding for video codec Enabled 
Optimize for 3D graphics workload Disabled 
Graphic status indicator Enabled 
 

We are publishing a desktop, not a single application. Does anyone have any further advice on this? 

[Michiel Roos1709158798]

To answer my own question, we solved this by removing the "optimize for 3D graphics workload" setting which was enabled in the graphics policy. Since setting this to disabled/default we've not been able to reproduce the flickering. 

[Michiel Roos1709158798]

And another update:

Summarized, the problem came back and we did a lot of testing.

 

The problem looks to be in the hardware encoder on the Nvidia M60/P40 cards. When we disable hardware acceleration for H.264 via the Citrix policy, the problem goes away. however with the software encoder we were getting a mouse lag which makes using the sessing a pain (and Autocad unusable), this was traced to the software encoder maxing out a CPU core. The NVidia K2 cards we have running most likely don't have this problem (there are a few other variables but we haven't tested with the same image). 

 

 This is still a workaround, seeing the performance of especially the h.265  codec we would still prefer to use the hardware encoder.