How it is possible to ship quantity from another lot

Hello Gurus,

I faced one issue, need to understand how it is possible.

We have One Sales Order which has two lines,

1. The quantity # 315 for Line 5.1 was picked from Lot # 1234 but shipped from another Lot# 4567. Line & Delivery is closed and Interfaced.
2. The quantity # 513 for Line 5.3 was picked from Lot # 4567 but due to insufficient quantity in the Lot, it failed to deliver the shipped quantity.

I would like to understand how it is possible to ship the quantity from another lot which was picked from some other different lot. (Ref Point 1).

Any help on this would be appreciated.

Thanks,

Venkatesh