Stop iPhone Screenshots Saving To Macbook

I've seen this brought up by a couple of other people, but the thread always gets shut down before anyone can write any useful advice.

Every time I take a screenshot on my iPhone or iPad, it automatically saves to my laptop as a PDF.

iCloud access to my photos is off. Universal Clipboard is off. And yet, it still happens every single time.

Does anyone have any solutions to this? It's extremely, extremely annoying.