H1b transfer back to my old employer (A => B => A)

[kannanmr]

I know this is a beat-up topic -- but the responses are so varied I thought I'd check with you guys to get the latest take on this!

I used to work for "A", I moved to "B" recently after they filed for my H1b txfr (pending -- filing ack rcvd). I have got 2 paystubs from them.

Now, "A" wants me back and they say legally I can start immediately with them, as they havent actually revoked my H1b with USCIS.

What do you guys think? Can I go back to "A" even though I have got 2 paystubs from "B"? "A" doesnt have to prove me to be in their payroll for this period?

TIA.