Your target is rich in Ha, and it shows up in your result, are you just interpreting the Ha signal as fogging? I believe you need alot more subs, like minimum 30, and these should be graded to eliminate any with poor signal quality. There are a number of image grading apps, Mainsequence has one that is excellent. Not every sub is going to be good, you should expect to discard some from every run. Good luck. Do some reading here, it's the download link.
https://mainsequencesoftware.com/Products/ImageGrader