I'm getting the same problem.
When I select my ZOOM L-20 audio interface I get this problem. When I swap to Windows Audio the problem goes away. When I swap back to the ZOOM L-20 audio interface the problem returns.
I also use Pro Tools with the ZOOM L-20 audio interface and have no issues.
I'm trying out the Studio One 5 demo at the moment and have run into the issue immediately. Not a good start.
Anyway it seems audio driver related, but I haven't found a solution yet.
I'm running on Window 10.