Assignments of closed activities disappear

Hello,
we are actually using v11.0.2 (checked changelog of actual version but found nothing) and are encountering the following problem:

Two users, having same Profile (Administrator) and both are not part of the relevant project - but in opening the details of a closed activity,
the list of assigned ressources differs. One gets the list of assigned ressources and the other gets no information (see attached screenshots).

Do you have an idea on what might be wrong?

Best regards,
Torben

We are using Version 11.0.2.
I checked "Change-History" of newer versions, but found nothing that seems to have changed in this case.

The "problem" I described concerns the same activity - opened by two different users, having the same profile (and so the same rights).
For this case I would expect the same behaviour - either the assignments are shown or they are not shown. What we get is that the assignments are shown for the one user and are not visible for the other.

We allready cleared the cache but without effort - the behaviour is the same.

Best regards,
Torben

I'm sorry to write you again

The problem is, that the checkbox you mention is not available (see first attached screenshot).
Cause my problem still exists, I just updated to actual version 11.1.3, but nothing changed. 

What I've found is some strange setting in plugin "ScreenCustomization" (see second attached creenshot).
Because of having a lot of activities and intensively using custom fields, I can't simply try a reset to standard disposition ...

If this is the reason why we don't see the checkbox (and I assume so) - I would be happy, if there is any chance
to get it back into correct position.

Best regards,
Torben