It's an oversight by Imgflip. I think this feature is brand new, but basically in the more normal meme creation page (I only have checked the one for "Create a meme", and not in other creation pages so far), there is a button next to "effects" called "A.I". If you press it you can put in an input for the ai to make something, but it does not change the watermark like if you went to the more purpose-built a.i meme making page.
It will probably be fixed in awhile, and I will send them an e-mail myself, but for now I'll just honestly state what made it.
Caption this Meme
