Starting with devices #1 + #2 connected, and in parallel connecting #3 + #4

When I connect Intercom #1 to Intercom #3, all works fine, and 4 intercoms can talk to each other.

If for some reason, Intercom #1 or #3 receive a GPS instruction, all the connections are broken, momentarily and soon after going down, they come back up and only connect #1 to #2, and separately #3 to #4.

At this stage, the intercoms are bugged and I can't establish a connection from #1 to #3 or even #4, and I only get a message Intercom failed, try again later.
The only way to revert this problem is power cycle all the devices.

Is anyone aware of this bug?