TYB
https://health-desk.org/articles/do-vaccines-contribute-to-monkey-pox-infections
According to this, Astra Zenaca uses a chimpanzee vector (that's just a nice way of saying "monkey pus".
Some of the vectors are the culprit.
Not everyone is getting monkey pox, only the people that got bad botched batches that were using a vector that was meant for monkey pox, and not COVID.
Astra Zenaca was more prevalent in Europe, I think.