I have a road warrior setup on PiVPN with a Raspberry Pi. Site was using pfSense, just recently changed it over to OpnSense. Set up the port forwarding in NAT and everything works fine.
The issue is if I connect to a Windows machine via RDP/Remote Desktop over the VPN, the session will freeze within a couple of minutes. Sometimes it will pick back up, sometimes I have to close the session and re-open it where I will get a couple of minutes, max.
It feels like a handshaking issue of some sort but nothing is jumping out in what would be different between OpnSense vs. pfSense (where it worked fine all last year). There are quite a few more options in the port forwarding for OpnSense and I'm working my way through them but thought I would toss this out in case someone happens to know and could share a quick insight!
OK after lots of searching around, resolution of similar complaints with OpenVPN on another firewall lead to discussions of UDP timeouts and then I found this: https://forum.opnsense.org/index.php?topic=3901.msg13753#msg13753
So I made that change and things have improved - I now get a hiccup of just a second or two every 30-40 seconds. I think I might be on the right path! Still digging...