I'm waiting to transfer from company A to company B on H1B. I know that once a USCIS receipt number is issued, I don't have to wait until approval to legally start working for company B. Because of the current circumstances and the amount of time I had to wait for this transfer, I'm considering not giving a two-week notice at company A.
My question is, is it legal for me to be on the two's full-time payroll for a week? I know it takes up to 15 calendar days to hear a decision from USCIS, and I can wait for the first week, but if possible, I'd like to work the second week at both companies and quit at company B if approval is granted.
If I do this, what happens if I'm not approved but worked for a week at company B?