The Canadian Ruling is to also give A the ball at point of fumble, with downs continuing. In this case, 1D was earned, so it's 1D/G @ B-3.
IMHO, this is a major screw up. IWs are bad enough, but to have an IW that involves the EZ.... ouch! Then, the R had to go to the reply two times!? Ouch!
I agree with Mussberger being an idiot.
