H1B Visa Stamping after Transfer/ Re-stamping?

Hello,

I have valid stamping until Mar/2022 with employerA and currently in India for emergency. Meanwhile employer B is going to apply for H1B transfer soon while my stay in India .

  1. Will this affect my entry to US provided if the transfer is approved and I want to join employerB after my return to US , can i still show my employerA I797 at port of entry or should i go for dropbox on the transfer with employerB?
  2. Can i join EmployerB while in india and travel to US with employerA Stamping which is valid till Mar/2022?

Thanks.