Wow. The ramp had better be getting paid off by the Patriots, because very little else would explain how they bugled this up that badly.

So either the ramp got distracted close to the end of offloading and forgot about the last cans.
Perhaps someone thought that they didn’t need what was in the last cans and purposely left them on board. At this point, proper oversight (Chiefs equipment MGMT, Charter Ops, Ramp lead etc) should have caught that the numbers of what was offloading wasn’t adding up.

The more serious problem lies in when the plane leaves to go to Newark. Did no one - the Ramp, the Chiefs, United - notice or were curious as to why there were hundreds of pounds in cans still loaded on to the aircraft? I hate to wonder if these cans were marked as scanned off the ac and the plane flew with a thousand pound load error to Newark...?

Many things went wrong for this to happen. Also very interested in the chiefs acting as their own ramp operation for their plane if not United ramp crews? Perhaps part of the problem here.

Also a note - The 737 the bags eventually went to Boston in cannot accept the LD2 cans (or any can for that matter) they were originally loaded into on the 764, so the bags must have been taken out of the cans and placed into the 737 bulk bin.