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I wondered the same thing. I don't think it's from a ship propeller or anything, as you always see a lot of lacerations. My guess would be a cookie cutter shark bite maybe??

Yes that makes sense. Here's a link to an Australian Museum page with photos of Cookie cutter bites/scars. The one on the Goblin shark is very round.
https://australianmuseum.net.au/cookiecutter-shark-feeding-scars