I've been using Access Server v2.7.3 without any issues in NAT mode.
The issue has been our web filtering software is logging all VPN users as using the single internal NAT ip. The filter is internal to our network so it can see internal IPs.
I have OpenVPN running on a HyperV with two NICs. One is public facing and the other is internal (10.40.0.100)
When I switched to routed mode clients were able to ping the local router 10.40.0.1 and other routers beyond it, 10.50.0.1, 10.30.0.1 etc.. but couldn't reach any devices, ie 10.40.0.101, 10.50.0.100, 10.30.0.100 all were unreachable.
Should I change the internal IP to it's own subnet and put it on it's own independent interface of the router like a /30?