https://prettier.io/docs/rationale#decorators
https://github.com/prettier/prettier/blob/main/docs/rationale.md#decorators

Relevant sentence:

One final thing: TC39 has not yet decided if decorators come before or after export. In the meantime, Prettier supports both:

This is outdated, the issue is closed and it seems they decided on either/or being valid

Since I don't use decorators, I'm not sure if by now, developers expect both to be valid, or if this behaviour is relatively unknown.