User blog comment:ArtDraw12/Say something positive about/@comment-31556666-20161128231616/@comment-11883116-20161129003938

But his role was explained back in episode 21. In episode 22 he started being a mole. Harold didn't even know back then. They could know it just by watching his actions and explanation of his role earlier.

Although the fact it took them so long means they possibly didn't watch episodes 21-22. Seems likely since Courtney couldn't contact them in episode 20.