I don't remember unfollowing someone(happened at least twice)
Only noticed this today and I'm pretty sure neither instance was a block and unblock.
One of them was still following me and I didn't later see a notification to say he followed me again so I can't imagine it would have been.
The other one I don't suspect was a block and unblock because when I did that to someone else earlier this year her comment and my reply to her comment were removed from my post(granted for whatever reason the number shows up) however in this case my comment and her reply to my comment is still on this other girl's post.
The only thing these two situations have in common is that I followed their accounts in the same physical location so it might be a reception thing, but idk...
Honestly too awkward to address this directly idk what to say if she does ask about it...