I've run into a similar issue, also having many other instances working in the field.
The problem that I can see is that the iroute works, within the openvpn space, but the OS underlay is not adding the route, so traffic doesn't go back.
If you raise the log level to 6 and grab the logs, you'll see if your iroute gets installed, then ssh into the pfsense os and perform netstat -rn, you'll se if the OS has the route.
Still haven't found a solution myself.