Custom activity card form not showing properly on timeline for all users

Hi,

We made a custom card form to display a phone call on the timeline with the fields we'd like.
As system admin everything works properly but as simple user you get to see a - instead of the content of the card form.

Does any of you have an idea how to fix this ?

We work on Microsoft Dynamics 365Version 1612 (9.0.14.12) (DB 9.0.14.12) on-premises

As admin :

As a user:

We have the same behavior for a custom email card form we made.

Thanks in advance for the help !