"Transparent" sessions
I see this problem too, but it's my desktop showing thru.
I am running version 2.2.0.0 Free.
The items that appear to "flash" thru the RDP window when I mouse around is my Windows gadget (CPU Meter) and many of my icons on my desktop. I am running StarDock's Fences 2.13, and when those icons are visible on the desktop, they blink/flash/bleed thru to my RDP session. If I "hide" the icons on my desktop, it's better, but it still happens.