Absence Planning Redwood Page - why does "View Details" show for some absences, but not all?

We're on 26B.

Absence Planning Redwood page - why does "View Details" show for some absences, but not all?

See above screenshot. For our "Holiday" absences, I can see why "View Details" may not show because our Holiday absences are uploaded via HSDL and don't go through approval workflow (through manager to approve).

But how come "View Details" is missing for other absences that for sure did go through workflow approval (through manager to approve)? At first we thought maybe because some of these absences are older and BPM task is no longer available.. but that's not the case with all of them. Some were recently submitted just a few weeks ago.