I sent my 372 into AgExpress and while they couldn't find anything wrong with it, it has worked fine for guidance and held and RTX fix for the past 300 acres of corn.  Unfortunately it is now not providing good GPS to my Gen3 2020 so my acres are wrong.

In the past I've had RTX issues when I keyed my radio mic.  The answer was to move the antenna as far away as possible from the RTX receiver.