Tricky finding where to set this, but was worth the effort.
In Server Manager, look under Hyper-V, right click and Configure NIC teaming.
Create a new team and expand properties at the bottom
In Hyper-V manager, open Virtual Switch Manager, Create Virtual Switch. Select the NIC team. If trunking will be used, set the VLAN ID.
By default the Cisco ASA has a TCP MSS size of 1380. On larger packets coming over a VPN tunnel, it won’t be able to process these. Microsoft RDP is the most common example although it can also be observed with protocols like FTP.
The quick fix is make this change on the ASA:
sysopt connection tcp-mss 1300
This will cause the packets to be fragmented, and pass successfully over the VPN and through the ASA.
Sources:
Layer 77 