This is zoomed in on the Ha sub, and the kind of weird stars that I end up getting. I use a bahtinov mask for focusing, but maybe it fell out of focus somehow. I am using a field flattener, but I've been experimenting with it as you can see in this other thread... https://www.cloudyni...ack-focus-help/
Okay then this is important information. You see in your single Ha sub how your star trails are going tangential around the center? That is usually because of too much spacing. Reduce your spacing by 2mm and try again. You might need to experiment with this. BUT,
if you do not do a proper PA and get good focus you might be fooling yourself with what is going on. Focusing with Bahtinov mask is fine but focus does change during the course of the night. I don't know how much time and what was the temperature change between the time you focused till you shot that sub. Anyways, my advice is:
Fix a spacing, PA, focus - Take a sub.
Reduce spacing, focus - take another sub.
repeat until you start seeing a change from tangential aberration to radial aberration. That means you crossed from too much spacing to too little spacing.
Regarding your image without the FF. Well, I cannot really know what is going on over there because the field is quite distorted. All the above mentioned reasons and beyond.
It will be much better if you debug all this things using your L filter or G.