How do I make the Microsoft RDP client for Mac play nice with Windows 10?
I believe the bitmap caching was an option with earlier versions of RDC on the Mac; but according to this link, it is no longer possible to change this. 

Duplicate IPs

Are there conflicting IPs on the network?

A possible cause I've seen given these symptoms is duplicate IPs. Duplicate IPs on either the Windows 10 box or the Mac can cause this issue.

Try refresh the IP (assuming DHCP) on one or both sides and monitor the stability.