OpenVPN causing router to crash

had a working openvpn client setup (connecting to a leaf bering router), keys expired so i regenerated and updated the client (advancedTomato). it died, but i knew a new release was out so i upgraded, now the same thing is happening! get all the settings set, hit 'Start', and i can see in the logs that the key exchange happens and all appears well.. right up to the point i lose all connections - last thing i see in openvpn log:
Wed May 2 00:28:18 2018 Control Channel: TLSv1.2, cipher...

OpenVPN causing router to crash