Am I correct: I understand your report as saying it's a graphics error--that is, the guiding is decent, but the graphs report offsets in DEC corresponding to dithering (but it doesn't do this for RA).
Are you using SEP MultiStar? Is the same thing reflected in the guiding page's graph?
Just in case it's some kind of temporary axis issue, can you reload the graph? That is, you could read-from-file from a different session, then go back to this one.
In general for guiding issues:
Please point to a full log uploaded somewhere (e.g. google drive) with verbose, File logging enabled for at least Indi, Guide, Mount and Drivers/Mount.
Also, though I may be able to find it in the log, not sure, please let me know all relevant parameters--e.g. screen shots of your guiding options pages
(Calibration, Guide, Dither & GPG) and the guide page itself.
FYI, this isn't an "affects everyone" bug--e.g. I dither too but don't see that in my imaging. Here's part of my graph from last night using the latest software. For no real scientific reason I tend to dither 2 pixels every 4th image.