H1B Start date is a week later than the receipt date

[ghanashyam_s]

I recently transferred my H1B visa from company A to company B via premium processing. The transfer got approved but I had started working with company B before the transfer was approved.

The approval notice says valid to work from 5/14/2013 but I had started working in company B from 5/9/2013. The approval notice has the receipt date as 5/9/2013.

My H1B from company A is valid till next year and is not yet revoked by my previous company.

Is there any problem in my status that I need to address ASAP or I am covered?

Can company A revoke my VISA for a date in the past? Can they revoke it effective 5/1/2013?