Another Interference ?
 

On deck batter in the circle and a throw from the 1st base gets away from the catcher and goes towards the on deck batter who picks the ball up and throws it to the catcher .
Runners were advancing to home just past 3rd and to 2nd 1/2 way .
The catcher was scrambling to get the ball .

To be interference, the PU must believe there was a play, ie, an opportunity to get an out on an advancing baserunner. We have a dead ball immediately, regardless; if a play for an out was possible, it is interference, runner closest to home is out, and all others return to last base touched at the time of the interference. If judged there was no play for an out, then we have a blocked ball, and all runners return to the last base touched at the time the ball was blocked.

Strictly judgment; your call.