One thing to check to make sure to use nearest point alignment in EQMod align tab options, the n-star does have issues when there are many sync points close together which is the case when refining alignment and sometimes it just doesn't converge and jumps around. Haven't had issues with nearest point alignment on permanently mounted EQ8.
I have left it on add point as it doesn't seem to do any harm with nearest point alignment. After doing taking down the mount for maintenance or similar I clear the alignment data, make a loose model by syncing in a few places (around 10 or so) around the sky and save that as a base alignment data which then gets loaded for every subsequent session. That way the first slew is usually already fairly close and plate solving does the rest. This is also useful during the light summer nights here in Finland or day time imaging of planets when plate solving can't be used.
I use EQMod align. Those erratic jumps sound a lot like what I had with my previous HEQ5 mount which had a bit loose power connector and that manifested itself as occasional serial port errors. I ended up changing the power connector to a screwed one and that cured those issues. If you enable logging for EQMod, does it report any serial errors? Or does the power led blink / fade or is it stable?
I'm not sure I have the same issue, but I had a lot of random tracking aborts with my SW EQ6-R Pro. Jasem researched the problem and it looked like the mount was sending occasionally random position information back to EKOS. So he suggested disabling aborts due to these positional communications by doing the following:
Go to INDI Control Panel --> EQMod --> Horizon
Then uncheck "Abort Tracking" and also set Limit GOTO to "Disable".
Finally, go to INDI Control Panel -->EQMod -->Options --> Configuration --> Save
It worked for me and (best I can determine) doesn't have a downside. EKOS will still abort tracking based on the altitude parameter set in the mount tab.
Hope this helps!
Mounts: Sky-Watcher EQ6-R Pro, Meade LX85, Celestron NexStar Evolution Alt/Az
OTAs: Celestron 8" Edge HD w/Celestron Focus Motor, Meade 80mm APO Triplet Refractor w/ZWO EAF
Cameras: ASI533MC Pro, ASI183MC Pro, ASI224MC, ASI120MC-S, ZWO ASI290MM
Raspberry Pi 4 with Stellarmate OS, MacBook Pro
thanks for the reply and that's what I actually made to normally run everything, but the issue is still there and I can't use pulse guiding but only ST4. Not a real disabling problem, but an annoyance that prevents the use of a lot of cool Ekos feature!
Good to hear that helped, yes the regular barrel connector is not a very good choice for powering a device that is constantly moving. Also there seems to be some tolerances that some cables fit better than others and thus might work better. Skywatcher has better connectors in some of the higher end mounts like EQ8, but I guess there is a cent or two to be saved by not using those in the cheaper models...