I have the same problem, any found the solution?, thanks.
Win7 & Win10 are your client desktop or your RDP target ?
2 FGT 100D + FTK200
3 FGT 60E
some FAP 210B/221C/223C/321C/421E
target RDP is Windows 7 and Windows 10.
When you choose RDP quick connect, make sure you select
Security: "Allow the server to choose"
Thanks this works for me FWF 61E