I've been testing this and while it's kind of funny, it should be almost impossible for this to happen.

The logo appears almost always despite having removed it from most of the images in the data set and although I can delete it completely, I like that rebellious touch of "Menoziriath" XD

PS: It can be corrected with the negative prompts: (((artist name))), patreon user, (((watermark))), (((web address))),