comment deletion

i recently had 4 comments by the same author disappear from my blog. inspection turned up they were switched from comment_approved = 1 to = spam.

i’m wondering if there is some sort of backend bug they exploited to have their comment removed, or if i might have accidentally flagged them for spam collection by mentioning the word “spam” in my edit of the comment.

not sure if this is a bug (either on the part of WP or spam karma), my misunderstanding how things work, or what, but any assistance is greatly appreciated.

thanks.