Interference with F3 on Fly Ball

[Manny A]

Juco game (yes, IM, it happened to me again ). Runners at first and third, one out. Batter hits a popup to F3 who is standing a couple of feet from the first base bag in fair territory, directly in line with first and second.

R2, who took a leadoff on the pitch, is sauntering back to the bag so that she doesn't get doubled up after the catch. She clearly bumps into F3 while the ball is still in the air, but not enough to phase F3, who is able to easily catch the popup just as R2 gets back on the bag.

I was doing bases, so I saw the bump from behind the shortstop. My partner and I didn't call anything. Between innings, I asked him if he saw the bump, and he confessed that he was watching the flight of the ball.

Reading 12.19.1.4 and the Note that follows the first paragraph, I'm not sure if this was interference or just inadvertent contact. If R2 had stopped or tried to get around F3, she could have been at risk of being tagged off the bag after the catch.

But, assuming one of us had killed it the moment of the bump, and ruled R2 had interfered, would the appropriate ruling have been R2 out and the BR placed on first base? Or would we also rule the BR out based upon what is written in the second exception at the end of 12.19.1.4?