Perm with future employer, need stamping with current employer


I am currently working for employer A and my employer said they will not file Greencard going forward. I am near to my max out date. I consulted employer B and they are ready to file my perm immediately without joining them , but they asked me to join them before filing i140.

I am leaving for india next week and need to get my stamping done with the current employer. Will there be any problem in my stamping if the future employer files perm. Will it cause any problem at POE?