I'll check my system in the morning but I believe it might be related to the time zone differences. I.e. one might be the server time, (ERSTELZEIT), the lot was created and the other might the lot creation time in the users time zone. (ENTSTEZEIT). If the lot was created close to midnight, you might also see differences between the lot creation date fields too.
This document explains this and actually shows an example for an inspection lot in QM at the very bottom of the page. It indicates one is the creation time in the server's time zone.
Global Time zone management functionality - Toolbox for IT Groups
Craig