LCA amendment petition validity is less than original H1B

[mahendra_mm]

Hi All

I have a H1B visa valid until September 2018. I had to file a petition recently for amending the work location. The new petition has come with a validity end date of March 2018 (less than the original H1 validity date). Does it mean the overall visa validity is now cut short by 6 months? Or is it that the new work location is valid till March 2018, but the old one is still valid till September?

Thanks,