My current h1b and i94 expires by end of september. However my current employer had filed for extension(normal processing) and i got the reciept notice. But one week back I got a new offer and start date for new employer is by mid of october. New employer is planning to do premium for transfer(before i94 expiry). There is 2 weeks gap between i94 expiry and start date for new employer.

1)Will I be out of status for 2 weeks if I join new employer after i94 expiry, although i have receipt from current employer.

2)In any case if in future the current employers petition gets denied or revoked or rfe whether it will impact my stay on reciept.

Thank you.

No. Your extension of status and change of employer petitions will bridge the gap between your I-94 expiry and the start date.
If the petition is filed before I-94 expiry, you can continue working on receipt and join the new employer when time comes.

If the extension of status is applied before the I-94 expiry, the period from I-94 expiry till the petition is approved is called period of authorized stay. Once you join the new employer ( after the transfer is approved), and while your current employer’s H1B extension is still pending, your current employer will need to withdraw the extension of status petition which is expected and do not impact your status.

Thank you for your response. By start date I meant by start date in i797 and lca.

My current i94 and i797b expiry - September 30th
Current employer filed for extenstion with regular processing
New employer going to file lca with start date october 17th and hopefully would get i797a with start date october 17th

So by your response if i get i797a approval with new employer. Days between september 30th and october 17th which i will work for current employer with receipt notice wont become out of status if join new employer. Right.

Thank you again.

Correct. Feel free to get a second opinion from your immigration lawyer.