H1B Transfer receipt received, can I work for both actual and new employers?

[Cishore]

I recently received H1 visa extension approval till end of 2020 through Employer-A and working for a client currently and now I have filed H1 transfer for the same client through Employer-B because of there is a change in the process at client end and Employer-A is not a prime vendor. 

My query is can I work for both Employer-A and Employer-B for few days (Max. 10 days) till my transfer gets approved? and Is it legal?

I have received H1 transfer receipt.

Appreciate your answer, Thanks in advance!

[gopalakrishnach]

I guess you cannot work for 2 employers on H1B. It will be illegal. You can have multiple approved and valid H1Bs but you can work only for 1 employer.