[Bob M.]

cmathews...I think you've got it. The first run ended with the muffed handoff (behind the line). Then the foul occurred--during the loose ball. By definition, that foul is deemed to have occurred during A10's related run. A32's recovery and subsequent run is immaterial to the enforcement for B's face mask foul.

JMN...IMHO, I believe you're reading too much into 2-25-10c. I think that this enforcement procedure refers specifically to situations where a change of possession renders the neutral zone obsolete, hence the references to "...interception runbacks, kick runbacks, fumble advances, etc." The rule probably could be better worded by saying "...fumble advances after a change of possession,etc." I don't think that this play qualifies for enforcement under 2-25-10c. Rather, the basic spot is determined by 2-25-10b, and the penalty is enforced under 10-2-2c(2).