About 10% of the email I get is span ending "You received this message because you are subscribed to the Google Groups "jan-09" group." It's being sent to an

About 10% of the email I get is span ending "You received this message because you are subscribed to the Google Groups "jan-09" group." It's being sent to an email address I know is not registered with Google. I'm far from the only one with a similar issue. See https://support.google.com/groups/thread/68075070/i-get-google-group-messages-for-a-group-that-i-didn-t-register-for-and-the-unsubscribe-doesn-t-work?hl=en https://support.google.com/groups/thread/68075070/i-get-goog... .