Emonhub out of control

Pieter’s previous appeal for help:

I can’t remember seeing anything resembling this before. It looks very much like something for @TrystanLea to answer.

Looking closely at the energy values, I wonder whether your thinking

is right, because the message count, which originates in the analogue front end, is incrementing by one most times (it went up by 6 in 250 ms in one place) and the energy is incrementing slowly as I would expect if the front end had been commanded to report at ridiculously short intervals. It looks to me as if a wrong setting has got sent from somewhere, but I can’t explain how connecting the Serial Monitor rectifies the problem. As far as I know, only Trystan knows exactly what is sent when the serial monitor is started.