how would you fix this?

[mbyron]

Under FED, of course, once BU signals foul the ball is dead by rule. The defense cannot record an out.

OBR is less clear about this kind of umpire error. The BRD has an OBR ruling that says "the umpire may reverse his call if everyone concerned ignored his initial signal." The umpire's error likely caused BR to stop running. To stick with the erroneous call would give the defense an advantage not intended by the rules.

I would stick with the foul call, apologize to the defense for the blown call, and explain that if it had been a double down the line and I signaled foul, we'd probably still stick with the call.

BU needs to do all the talking during the explanations.