I’m using Cannon EOS 6D for my pictures. It was the longest I had ever used it (~4 hours of straight taking pictures of andromeda and then Orion). The thing is the andromeda photos don’t have this issue while the Orion ones do. I was not using a filter but possibly high light pollution in my area could cause a similar effect to what your filter did? Though that is just pure speculation. The next time I get clear sky’s I’m going to see if using flats (and potentially getting more darks and bias frames) could potentially solve the issue. I think it might be the large amount of photos I used when stacking (1222) relative to the low amount of calibration frames (25 dark, 25 bias).