I was running ekos/kstars 3.4.3 on my raspberry pi 4 with my Skywatcher eq6r mount.
Sometimes when I try to slew/goto, it will be stuck at a place near the selected target. There were no snagged cables or anything to limit the mount.
Note the following lines(this happened multiple times in the log file as I was trying to get it working), it seems like ekos was commanding the mount to slew but it won't. I don't know if it's the mount's or the software's fault that caused this problem, but I'm assuming ekos because the problem disappeared when I restarted ekos. Also, there's a higher chance of this problem after the mount goto-ed with "sync" enabled.
[2020-10-06T17:12:41.382 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto (1): RA diff = 86400.56 arcsecs DE diff = 0.03 arcsecs "
[2020-10-06T17:12:41.387 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative goto (1): slew mount to RA increment = 60, DE increment = 0 "
[2020-10-06T17:12:41.433 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Checking backlash compensation for axis 1 "
[2020-10-06T17:12:42.420 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto (2): RA diff = 86401.01 arcsecs DE diff = 0.03 arcsecs "
[2020-10-06T17:12:42.432 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative goto (2): slew mount to RA increment = 109, DE increment = 0 "
[2020-10-06T17:12:42.442 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Checking backlash compensation for axis 1 "
[2020-10-06T17:12:43.436 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto (3): RA diff = 86401.01 arcsecs DE diff = 0.03 arcsecs "
[2020-10-06T17:12:43.449 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative goto (3): slew mount to RA increment = 108, DE increment = 0 "
[2020-10-06T17:12:43.463 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Checking backlash compensation for axis 1 "
[2020-10-06T17:12:44.451 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto (4): RA diff = 86401.02 arcsecs DE diff = 0.03 arcsecs "
[2020-10-06T17:12:44.464 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative goto (4): slew mount to RA increment = 109, DE increment = 0 "
[2020-10-06T17:12:44.479 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Checking backlash compensation for axis 1 "
[2020-10-06T17:12:45.471 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto (5): RA diff = 86401.02 arcsecs DE diff = 0.03 arcsecs "
[2020-10-06T17:12:45.485 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative goto (5): slew mount to RA increment = 109, DE increment = 0 "
[2020-10-06T17:12:45.498 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Checking backlash compensation for axis 1 "
[2020-10-06T17:12:46.491 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto (6): RA diff = 86401.02 arcsecs DE diff = 0.03 arcsecs "
[2020-10-06T17:12:46.507 CST INFO ][ org.kde.kstars.indi] - EQMod Mount : "[INFO] Iterative Goto Limit reached (6 iterations): RA diff = 86401.02 arcsecs DE diff = 0.03 arcsecs "

Attached is (one of, as I restarted ekos to get it working) the complete log file from yesterday.

+1 for this issue. I had it last night when I was imaging near the Zenith and I couldn't for the life of me work out why it was happening. Just like royy, I restarted my RPi 4 with astroberry and it worked fine.

The log messages that royy posted contain values like "86401.02 arcsecs". There are 24 * 60 * 60 = 86400 seconds in one day OR in a circle when expressed in hours as usually is the case with RA so my guess is that that value means that Ekos mixes up seconds of hour (24 * 60 * 60) and arcseconds (360 * 60 * 60).

Interesting find! I checked my logs from that night and sure enough, every time this error occurs the RA diff was 86400 +/- 2 arcsec. The only thing I'm using that is different from the majority (since I didn't find anyone with the same problem except mattbaker) and is related to time is the GPS NMEA aux driver. I wonder if a bug in that driver caused it?
Anyway, thank you for the useful insight! (now think back about it, how did I ignore such an obvious pattern haha)

To rule out the possibility that this is due to the NMEA driver, I ordered a GPS module. Will test it out once it arrives.
PS. I meant "target" in the title. Doesn't matter but I'm a bit OCD lol.