H1b portability question

[calmese]

Does any one happen to know that if your H-1b got transferred twice, say first transferred to Company A, then later transferred to company B, is it legal to work for company A? If put another way, say Company A filed H-1b portibility for you and got approved, later company B did the same thing and the petition also got approved. Would it be legal to go back to Company A to work for them? Any input would be very much appreciated!

[jaxen]

Timelines are important.If within 60 days of working for company B, you go back to company A, it might be legal. Give more accurate info..

[calmese]

Jaxen, thank you so much for your reply. My dilemma is:

worked for company A, had their work visa (the very first one H1)
got job offer from company B, they filed h1b portability through Premium, got approved in 2 weeks in the middle of May.
Company C also filed H1b portablity later in May but through regular way which takes 4-6 months to get approval.

never started working for Company B.

quit company A and joined company C in the middle of June (based on H-1b transfer valid upon petition receipt)

Now my question is would the approval of H-1b tranfer to Company C have problem??? since I transferred once to B but i never worked for them.

Next question--if I go work for Company B which I have valid H1, but would the later approval of Company C H1 cancels out my Company B work visa???

Thanks for your help!