Not sure if this is a bug.
When I take off in a FM2 the manifold pressure is about 45. If I hit WEP the gauge dosent move. As time goes on the gage slowly moves to 40lbs and if you hit WEP it jumps to 50 lbs(which is correct)
Then once in awhile the gauge freezes at one setting and will not move if you engage or disengage WEP.
Not sure if that the way its supposed to act.