So for troubleshooting purposes, I would suggest disconnecting the interconnect wire, but leaving them powered. You’ll want to reference the user guide for how to hook them up as a single station and do that. Then you can see which one is actually giving the fault.
If none of them trigger, then the problem’s probably in the wiring. Reconnect half of them and see if it happens again. Switch halves if it doesn’t, reduce by half if it does. Keep going until you find the connection causing it.
Keep in mind that you’ll still want the interconnect wire intact, so make sure to connect the ends together in the bays of the alarms you’re disconnecting from the interconnect network.
Have you tried cleaning the port out? My last phone had issues with a wobbly cable and not always connecting when I plugged it in. Turned out a bunch of pocket lint and other debris got packed in there, and once I cleaned it out it worked like new. Had to do that twice in the 6 or so years I owned that phone.