I don't know whether or not it is a bug for a three, but for Watched Forums, topic notices/post texts are being sent to users who no longer have access to that particular forum. The User once had access there, but even after their access was removed, the User still continues to receive the topic notices/post texts.

Is this a bug?

I woudln't really call it a bug, more of an oversight lol...

Then it's a bug.

Ok fine, users being able to receive topic information about forums they don't (still) have access to I'd say is a bug

Yep, definite bug that needs fixin.

Is this an involved fix requiring at 7.1.1, or can you inform us of a fix here?

Until I figure out the fix, I can't really say.

Have this fixed for 7.1.1. It's a bit of a complex fix, so unable to post.

Glad to hear it... I was thinking of the possible security issues and though of...

Say you have an admin/mod forum, and modb is thrown off staff, but they're watching the forum, they'll get emailed on every post, so if you're talking about them and their name is in the subject, they'll get mailed and you may get emails of them peeved about them being talked about... Which can lead to dirty laundry issues