Apparently, real world events. I almost dropped my comic because of Covid, because there is a eerily similar epidemic in my story, and I was afraid that the new, entirely different relation people have now with such diseases would alter the mood of my story too much. I did overcome that by tweaking my fictional disease to be less Covid-like, but it was a close call.
I'm also afraid of getting the wrong audience like what happened to you @lilithfairenwrites (this sounds awful, I'm sorry you had to go through that).
My specific worry are crazy BL fans. Not all BL fans, they are mostly fine. Just the crazy ones. I saw some LGBT stories getting comments demanding disgusting/illegal pairings, demeaning characters for not being toxic jerks.. and such, it terrified me enough to make me change my story a good deal (I'm actually going to put all the romance parts in a side comic to avoid possible 'contamination' of my main comic. At this point my main comic is too small and too much of a different genre to be a target AT all).
But the most probable reason I would drop my comic has nothing to do with audience, it would be a worsening of my back pain. Drawing is one of the activities that gives me pain.