I don’t think it’s anything to do with the new version.
I have two RS1Ds, one in a big city and the other at our beach cottage.
The one in town never has such spikes, but the other has them quite often.
It is at the very end of a long transmission line and we often get power surges.
One such surge blew every electrical device in the house and threw the neighbour’s microwave oven across the room. Mostly, they aren’t so big and we don’t notice them.
So, for me these spikes indicate the frequency of power surges.
Of course, yours may be different.
i too think this doesn’t have anything to do with the upgrade. and i can confirm that version 0.19 contained no modifications to the data capture portion of the system whatsoever. differently said: nothing in version 0.19 would explain the existence of such a spike.
thank you @ivor, i will try to re-locate the unit if this continues (must be environment issue then). and add surge protector to power outlet, good suggestion @TideMan, thanks