15b5 Random Artifact bands during playback / Scrubbing!

2013 Mac Pro 12 core dual D700's, High Sierra 10.15.3. Beta 5 -- Cutting a short film and everything is fine. Then about 2 hours later during the same session - horizontal temporary artifacts began appearing on playback or scrubbing clips. When I frame forward and backward, the artifact lines (see attached picture) will not stay in the same place - which tells me it has nothing to do with the footage. Sometimes they'll appear and disappear at random. Tweaking random inspector properties makes them go away for awhile but they come back eventually - restart doesn't seem to help. Strange part though is that I exported a short clip to see if the footage would be clear but the artifacts get burned into the resulting file

Is this a beta 5 bug or known issue? Trying to figure out if this is the program or my machine/graphics card starting to fail.

[Peter Chamberlain]

In preferences, system, is your GPU processing set to auto or OpenCL?
Try the other.

I have GPU processing set to OpenCL, GPU selection set to Auto. Mac Display Color Profiles OFF, Use 10 bit precision ON, use optimized image transfers OFF, Always run Fusion in cpu ON, Use GPU for red player OFF, use easydcp decoder OFF.

What are the correct settings to use on a Mac Pro with dual D700's? Metal / Auto?

Also there are random artifacts when rendering to h264 as well.