What’s happening?
The some fields configured to "always show" on the Phone Call card form are not appearing correctly on the timeline in Dynamics 365.
Reason:
The timeline control in Dynamics 365 is designed to display only up to three fields on the timeline card form. If more than three fields are configured, only the first three fields will be displayed.
Resolution:
Ensure the desired fields are positioned within the first three fields in the timeline card form configuration.
See Add and configure the timeline control in Power Apps - Power Apps | Microsoft Learn for more information.