openVPN when connecting from a TMobileHI sourced site to a TMobileHI sourced site

I have a B One set up at a site with a fiber ISP AND a Tmobile Home Internet gateway as WAN sources. I’m finding that I can VPN into the network when I’m out and about (and NOT at a site with TMobile Home Internet) but it doesn’t work correctly when my remote DOES have TMobile. The TMobile gateway obviously uses the 192.168.12.x subnet and I’m wondering if this has something to do with it. I disabled the Tmo connection in the openVPN settings but I’m still having issues. btw, my remote client can connect - that doesn’t seem to be a problem. But reaching anything on the local lan at the peplink router/openVPN server site does not work.
Interestingly, I have another Peplink router at another site that has a pepVPN connection to the site in question. I CAN use openVPN to reach this third site and then, through the pepvpn connection, reach devices at the site in question.
Anyone know right away what the issue is?

Lastly, I’ve noticed that the balance 20x OpenVPN settings page has an additional field that is missing from the B One; The “Connect to Network” setting. I’m quite confused why this would be missing.

Hello, @warren1

This parameter is to be used to connect a specific network.

Do you have more then one network of this device?
This explain why you have this option at your device.

Have you configured some firewall rules?