Question:

If both Jammers are called off on penalties, but the jam ends before the second Jammer takes her seat in the penalty box, is there a Jammerless Jam?

Answer:

In the above situation, the Jammerless Jam rules apply, but new lineups are fielded because the previous jam has already ended. The original Jammers serve their time in the penalty box as Blockers, and the teams will begin the next jam short those Blocker positions.