There’s the rub. If you look at M82 above and imagine it occupying about a full 3/4 of the frame, you can see that there are very few actual stars in frame. 3910mm plus a 4/3 sensor means a very tiny FOV. Few stars - in and of itself - is not a problem. AF works very well even with just a handful of stars. But when you have, say, 8 stars at an HFR of 3, and one galaxy portion with an HFR of 12, the average will be drastically skewed high.
I’ll run some focus packs tonight, skies permitting.
Tim