In my experience with my own KNX installation as well as discussions with other members installations I’ve came to the conclusion, that there is no bridge configuration that will work a 100% in all situations. My feeling tells me that different vendors KNX IP interfaces simply have different implementations and therefore show different behavior.
That said, I can only say that my MDT based IP interface in a quite old software version (MDT KNX IP Router, SCN-IP100.01, software version 1.0) works best in the router mode. I never got it to work with tunnel mode.
I guess you simply have to try and error your configuration until you found something working. Good advice is always to restart OpenHAB and do some test, before assuming that a given configuration is better than others you have tried.
You can refer to one of my previous posts, like this one: https://community.openhab.org/t/openhab-3-0-knx-dont-have-channels/111409/24 to get my configuration.
If I do a disable/enable cycle the KNX thing (the heating actor), I can the the relevant bus messages in the group monitor like this:
So OpenHAB issues a group read telegram coming from the device 0.0.0 (the router) and is answered by the heating actor and send back to OpenHAB.