I noticed that others report a similar issue. I just migrated up to the latest EKOS/KSTARS build (StellarMateOS 1.5.1) and have tested on both a RPi3 and RPi4. The mount tracks and points fine but will drop out of track mode into an idle state in what seems to be random intervals. Sometimes it does this just s few minutes after acquiring a target and sometimes tens of minutes later but it does not stay in tracking mode for even an hour. This is a behaviour I have not seen before. In the past I used mostly the RPi3 and found it to be "rock-solid". Any wisdom out there on the issue?

So any mount abort command would cause it to stop tracking... maybe the logs show when and why this is happening?

Thanks Jasem - I suspect it is finding a horizon limit or something like that and will run some tests/logs today. Will let you know what I find.
PS - I was delighted to find QHY PoleMaster support!

Brian

I find it is more stable when your EQDir cable is plugged directly into the Pi, so avoid using a hub for it.

Thanks for the tip - will give it a try!