Hmm this is the second time my Mastodon was suddenly logged in as a random user from my instance. That's troubling.
@ruud wuuut. My first guess is cache issues but that would mean your instance uses a cache for its API calls and not just static media.
@stemid I wouldn't know where that cache would be configured.. I run Mastodon in a docker container, behind a nginx reverse proxy. Nothing special.
Generic Mastodon server, open for registrations.