Rule question from Montreal-BC game

Last night there was the two fumble play where BC was given the ball and the second fumble not counted.

When Montreal got the second fumble it put them on their original line of scrimmage.

During the play review, Glen Suitor said that if Montreal maintains possession, by either an incomplete catch or both fumbles counting,it will be second and ten.

Is this correct?

Or is it if Montreal gets the ball back during the play, behind their intended first down line (after the BC fumble) at the start of the play it is a first down from the new spot. This being because the downs reset the instance possession changes and not at the end of the play.

Please only answer if you are 100% sure as this has been debated for years. Or, can you direct me to a better place to find the answer?

Cheers
Craig

If there are two fumbles on the play, the team obtaining the second fumble will have a first down at that point. So if Montreal fumbles, then the Lion fumbles and Montreal recovered, it would have been Montreal ball, first down.
Suiter was wrong!

Yeah, the ref signaled a first down Montreal, before the call was overturned.

And obviously, had they ruled an incomplete pass in the first place, it becomes second down.

Yeah I saw that too.

Thank-you all for your reply.

Craig