Oh, I saw a video in 2021 in which a retired doctor/uni. prof. explained AZ complications (it was someone from the UK) were most likely/could be related to how nurses handled the needle and where they stung it. Like, he was concerned about the lack of instructions given to vaccinating squad. I blacked this info out because it was too much of a yet another thing I had to watch for at the time on top of others but for my first booster I had a chat with the nurse about the dosage of the booster and... yeah... better check these kind of things out yourselves, things can go wrong really fast (and mark your legs and operation instructions on your body before going under the scalpel :).

Edit: not sure if it's the video I watched but it's definitely the guy https://www.youtube.com/watch?v=nBaIRm4610o