I found one more curious correlation with the first of my two CPU temp spikes. Weirdly the amount of free storage in Homey seems to have gone up markedly at the exact same moment as the start of the first CPU temp spike. I made no change to Homey e.g. installed/uninstalled apps at that time to explain it. No such correlation with the 2nd CPU temp spike though.
Complete speculation based on very little understanding of how these things actually work but I wonder if Homey cleared out some of the very large Swap file which I had before I did the CM4 mod?
On my side I haven´t found a pattern yet - sometimes I have 3 unexpected reboots on a day, and then, my homey runs for 3 days without a reboot, but always with those flow-effects.
Well, somehow the Homey Web interface when updating Advanced Flows got very slow, not updating so fluently like in the past and yes, I observe it already longer time.