H1-b visa stamping possible with current company valid petition when h1-transferred

[senthil2006]

Hello - I have a valid H1-B extension petition approved recently till 2020 with my current company A and hence I got an offer from Company B and applied for H1 transfer and got approved but i have not joined yet. Hence I am planning to go to India for short vacation and need to go for stamping.

Will there be any issue to go for stamping with current working company A?

And after coming from India, Can i join to new company B??