L1 to H1 COS - Urgent clarification required

[prunid]

I got my COS approved from L1 to H1 on 15 Dec 2011. My previous L1 was valid till 2013. But I worked for my previous employer till 12/28 and only then joined the new employer on H1B.
Is this going to cause a problem in the future?? Eventhough its a vacation time and a lean period, will this affect big time like Stamping, H1 Transfer etc..Also need to know, if I do a transfer, who will respond to queries if any questions are raised by USCIS.

Thanks..

[kabkaba]

It should not be a problem.