Please post blender issues in the blender sub-forum.
So are you using both GPUs? But one works with Low/Med/High modes? What about Full.
Also note there is limited support for 580 in low/med/high currently. Will be updated soon.
Hmmm, That's strange. Other users are ok on the NV 2080 card. One thing we have seen is sometimes the latest Windows update is not installed? Any chance that's the case here?