There are several answers which have been flagged as "not an answer" which were indeed answers. Consequently, I flagged them with "invalid flags". Why is it that all of those flags were disputed? Here is an example:
This answer was flagged as "not an answer" (I think), but it clearly is. I used to think that perhaps my flagging was flagging the "invalid flags" flags as invalid flags, but this answer changed my mind. I was the first person to flag it with "invalid flags" (and many others flagged likewise). Why was this flag disputed?
My flagging history clearly shows several other such cases.