Autofocus failed on me last night because of clouds and/or tight settings. The first failure is legit, but later it struggles to restart, with subject message.
The UI shows both Autofocus and Stop buttons active at that point. Sometimes I was able to resurrect it by pressing Stop a few times at the right moments. Other times I was more impatient than lucky and ended up stopping the restarting the Scheduler.
The first two logs contain a couple of instances of "discarding start request" . The third log contains the whole multi-hour series of them. I am not sure whether it stuck in a bad state or it was too cloudy all that time (it was intermittently cloudy the whole night).

I think this is invent.kde.org/education/kstars/-/issues/53

-Eric

Last time I tried the latest Jan 9 version. It seems, both old problems are gone. No 'discarding start request'. Linear algorithm reverts focus back to where it started.
Yet, the focus position drifted all the way from 16500 to 28000 in 6 hours. See the attached logs.
Only a few first focus attempts were somewhat successful. After that clouds rolled in, so star detection errors are legit.
From what I read in the log, failing focus session reverts the focus asynchronously. Next focus session starts quickly before focus motor reached target position and reads current position, not the intended one. So, either the reverting operation should wait until the motor actually completes the move. Or reading 'current position' should yield the target position if there is move command in flight. My diagnosis may be wrong, of course.

I did see this error (for the first time) using 3.5.2-1857_gdc14609eb (Jan 26). Klicking 'Stop' multiple times did finally stop the AF, but left the focus position random.
I downgraded to 3.5.2-1841_g74e0dac19 (Jan 21), that one worked fine.

I also have the issue that I cant stop the autofocus routine. It keeps “restarting autofocus” after I hit stop. It keeps doing that even though I press stop repeatedly over and over. It recognizes that I pressed stop, because the routine does interupt, but then it restarts again right away.

Is there a fix for this?

I have this issue too, I'm on the Stellarmate beta channel. Last night it clouded over so I aborted a sequence and went out to put the flat panel on to use the time to take flats.
I loaded my usual camera file for LRGBSHO flats and clicked start and Ekos started to try and focus my scope instead of using the already generated focus positions for flats (this is ticked as enabled).
I was unable to stop the autofocus using either the stop button or the stop focuser motion button. Only able to resolve by disconnecting Ekos and reconnecting.

I'll see if I can dig out the logs and raise a ticket.

There is a pending PR to fix this issue: invent.kde.org/education/kstars/-/merge_requests/212

So please just wait until it is tested and merged.