[This post][1] on Meta Stack Overflow suggests that when you vote to close a question, any flags you also raise on it are nulled to prevent an unnecessary increase in helpful flags.  

I assume that this has been extrapolated out to answers and that you cast a delete vote as well as raising the flag?  This would likely result in the flag being recorded as 'none' to fit the pattern Jeff describes for questions.


  [1]: http://meta.stackoverflow.com/a/106360/176080