Error 77 after Upgrade to 1080Ti | Edit: Optical Flow issue

I added a GTX 1080Ti to my machine (See specs below). I'm constantly getting error 77 once I play any footage in my timeline. When rendering it stops immediately and gets a timeout error after a while.
I'm working in an 8K 60p timeline and basically just want it to render out (at any speed). For editing I usually scale it down to a 4K timeline which worked perfectly on my 1070 so far. Until you bump it up for final render and GPU memory is an issue. Thats why the 1080Ti came to solve this issue.
Anyway, hope to resolve this soon. Quite a bummer.
Specs:

Resolve V15.0.0 B.057
Windows 10 Pro
2x Xeon E5-2697V2
128GB RAM
1080Ti
1070Ti (used for gui only)

Log:
Can't attach Log File (77MB??)

Try again with the 1070Ti removed. When using multiple GPUs they should not be mismatched.

Ok 1070 removed. No difference with the single 1080Ti. Same error once I hit render.
But I removed the optical flow frame interpolation from the clip and I got to render properly.
So I guess thats something which can be fixed more easily than multi-gpu issues?

[Peter Chamberlain]

this may help

https://forum.blackmagicdesign.com/viewtopic.php?f=32&t=75431

edit
thanks walter
sorry, cut and paste error.. this one

viewtopic.php?f=21&t=69837&p=389804#p389804

this may help

viewtopic.php?f=32&t=75431

this does not make any sense...

[Shrinivas Ramani]

Martin, could you post a link to your log archive on a file-sharing site?

(see viewtopic.php?f=21&t=69837)

Sure, here you go: dropbox.com/s/f1nug4qsw6y0jqo/DaVinci-Resolve-logs-20180618-190300.zip?dl=0