Note to oneself.... Before repairing ZigBee mesh, starting to blame a new ZigBee wall switch put in (repeater) breaking my ZigBee or blaming the tuya blinds for losing pairing.... Trying to repair the Sonoff water Solenoid...
Check your ZigBee antenna(s) on your c7 (edit: c8)..... Far out. It has loosened and was temperamental so sometimes worked... And likely not so good for devices further away.
That was an easy fix after going around in circles... Note to anyone. Any mesh problem.. start with checking the antenna
My first assumption is always "it must have been me...", which explains my lack of topics asking for assistance, I can usually sort out many of my problems by looking in the mirror
Well done for posting on your own.... "experience".... For everyone else to learn from...
In ancient times I was a navy electronic technician working on radar systems. The repeaters were a monstrous pile of vacuum tubes. Typically 100 plus. As a newbie, straight out of ET school the first thing I would do is look at everything closely and then start tapping on the tubes in circuits related to the issue at hand. Frequently there would be a flash or odd color in one of them. Replacing that tube would often quickly solve the problem. As I became more skilled I'd show up with an oscilloscope, delve into offending waveforms, and narrow down the source. Once identified, it was not unusual to tap about and then see a visual indication in the failing tube. It is really easy to get deep into the weeds, overlooking the easy and obvious.
tatooed on my forehead. 
Welcome to the club!!
