Thanks fo the comment. Can you say why my code throws this up and can be ignored ?
I don’t want to explicitly list entities otherwise I need to maintain every time I change things. Eg, I am gradually splitting my heavy use items into peak/shoulder/offpeak to track what is costing most and this string matching code will catch and ignore them without amendment.
Oh, right… I got halfway there, but see now where I went wrong: the listener subscribes to changes in states.sensor and the warning is that HA is preventing a recursive loop, because the sensor being updated is in there. What I missed, was that the filter is obviously after the fact and hence the warning remains.