I have just earned the "Yearling" badge although I did not do anything on meta, I did not even vote on a meta question or comment or even open it at all. I did indeed earn > 200 reputation in a year but that does not make me a meta user. The meta membership is attached to the main platform like on any other Stack Exchange, that is clear, but without any activity, I did not think to get any badges at all. Now it is >250 on the main platform, with the last rep a week ago, that cannot be the reason.
Is this a mistake?