Hello ,
What operating system are you using? There have been a few reports of issues similar to this that were actually caused by the UI scaling in either Windows 8 or Windows 10. This feature didn’t exist in Windows 7 and prior. If you are on one of those versions, please try setting the UI Scaling for each monitor to 100% and see if you get the same results. I’ll be trying to reproduce this soon as well. While it is a niche case and getting an adapter will be better in the long run, it’ll still be good to get reported.