In the log it is sending 0ms DEC pulses. I had RA guiding only on, and the two axis calibration was off, so RA only guiding was working fine. Manual dithers failed as well.

[2021-12-30T22:26:25.208 PST DEBG ][] - Dithering in progress. Current 112.23 310.043 Target 122.317 310.523 Diff star X: -0.152848 Y: -10.0973
[2021-12-30T22:26:25.208 PST INFO ][] - "Warning: Dithering failed. Autoguiding shall continue as set in the options in case of dither failure."

Checking the log it is reporting an offset in X before failure.

Looking at the code leads me to this line here :

So X and Y offset must be under 1 for the dither to complete. That can't happen if we are only guiding in RA.

The internal guider should be checking the RA and DEC settings to determine the directional vector, and/or it should ignore discrepancies in an axis for which guiding is disabled.

Let me know if this should be a support ticket. Dithering was one of the 2 big reasons I wanted to start guiding.