Hello,
Sorry to hear you are having issues. But, I can not answer your question, since I don't have this issue on my two monitors setup. But, if I remember correctly there was a report from a user where the issue was solved for him on his system. What I can suggest, you could do the 30 days trial on Fences 5 and see if it resolved on your system.
Thank you.
Basj,
Stardock Community Assistant.