We're working on a solution for this one / hopefully we'll have it out tomorrow. Can you try lowering your graphic settings/resolution & see if you still have it then ?
I was already playing in the lowest settings and unticked everything except for the 60 FPS. It is rather random, but it only happens during RTS. I tried using the support thing, and I got arbitrary results on "DirectX" Sometimes it's "Unknown" then sometimes it's "Passed". I used dxdiag and I'm using DirectX 11. I don't know if Direct X could be relevant though.
Anyways, I already sent a report to support with the report. Hopefully, this problem will be fixed by tomorrow. can't progress through the storyline without this fixed, so I'll just wait patiently by then. Thanks for the heads up by the way!