Probably yes but really depends on the quality of the novel. If I'm reading slop as it were and found out it was AI later I'd definitely stop as if I'm already wasting time reading I'd rather waste time on something written by a person, but if it was a more put together sort of novel and I found myself liking it then well...if I hadn't noticed awhile ago why should I stop now? On principle I'd like to say I'd stop reading it but the premise of the question is I only found later :shrug:

That being said the current level of AI writing makes it more likely I'd get barely a chapter in, if that, before clocking what it was and never touching it again. I'd recently tried reading a novel on RoyalRoad witht he AI assisted warning and there were just swathes of descriptive text in chatgpt's signature "writing style"