Did you get any response to this? I wouldn't have noticed the auto-claims either if you hadn't mentioned it.

I also noticed this morning that I had voted on a post from an author that I've never supported (i.e. a user that I don't auto-vote)... and I'm not on a curation trail.

It pains me to say this, but I've removed the authorisation that steemcurator01 suggested as this is the only possible reason for what's happened.