The activity stream reveals "secret" moderator comments
I usually don't use the acivity stream, but today I did and it sees like it lets me see "secret comments" (not visible to me) if the are liked.
I wrote a bug report on that:
https://answers.sap.com/questions/101371/bug-activity-stream-shows-non-existing-comments-be.html
best
Joachim
Ahhhh ok....that explains it! I noticed the same thing but thought it was related to people then deleting comments before I could see them. Nice work, Sherlock!