A more "normal" stamp would look like this...

Your stamp is given the variety name of "misplaced watermark". It could be argued that a mis-cut sheet is just as likely. Anyway, I believe
rare might not be quite true but
uncommon is accurate as the misplacing of the watermark also gives rise to the no watermark variety as the opposite side of the sheet to where you stamp is located would be a corresponding blank space. So, it might not have the same cat val as a NO watermark but certainly way above a normal. Research. It is not quoted in Gibbons Concise so is a more esoteric item reserved for the Specialized Catalog.