Gap in the approved H1 Petition

Hi , I applied for H1 Transfer on June 16th and started working for the new company on June 21st 2017 using receipt number. My previous employer said he would send the revocation request in one month, hopefully he should have sent it by August beginning. Now the new Transfer petition is approved on Dec 5th. And the dates in the i797A says from 12/05/2017 to 06/12/2018 . seems like they have given only for 6 months. but what will be my status during the time when my previous employer sent revocation(August) to Dec 5th? In fact from June 21st to Dec 5th , I have been working for the new company , but my i797A dates are not starting from June 21st, is this an issue for H1 Status or GC processing which i plan to do in another 2 months? how can i resolve this if so ?

Dont worry about your previous petition. The revocation request has to be approved by USCIS, after your previous employer sends it, for a gap to appear. So, there is currently no gap in your status. You are in good hands now that you have your transfer approved.

understood, but i am not sure when it got revocated exactly, if it had been revocated even before the transfer approval, does that pose an issue to my status ?

If the revoke application submitted by your previous employer was approved, you would receive a USICS notice that your earlier petition has been revoked by the previous employer. If not, you will receive one in future. Usually the revoke takes more than a year by USCIS to be processed and approved once they receive it.

Thanks Ramanan for your clarifying replies.