As Paul said, we have been testing our hypothesis for about a week or so now using a simple prober I wrote, and we can relatively reliably expect our fans to lock up.
I am not sure it’s the HA that is the problem here, but I have to confess, I have not tried running only the prober, without the HA integration being active. That may be an interesting experiment.
But… while I do not have a solution for our problem, there MAY be a workaround.
I noticed in the MF app there is an option to reboot the fan. I believe rebooting a fan daily may mask the underlying issue, combined with a less aggressive polling from HA (mine is set to 2 minutes, and my fans lock up about once every two days without my prober running).
Jim - since you did the heavy lifting for figuring out the REST API, save me the time for having to do packet captures - do you happen to know what the reboot command in the API is? I’d love to try out this little workaround.