Expire date doesnt appear on certain lot

Hi experts,
I am facing issue as in screenshow below. It should have the expire date to be auto generated.
However, for the same part number some other lot have expire date being auto-generated but some doesnt and it happens on several different lot as well.

Does anyone face such issue or know how to solve this so that the expire can be auto-generated? Thanks in advance for the help.

This is the one which has expire date shows up.