iCloud contact lookup during inbound call.

Strange one.

We have a user that has recently been migrated from an iPhone 13 to a new iPhone 16 - backup/restore was done via Configurator. Now, contacts stored within the iCloud account and present in the phone will NOT 'look up' on the inbound call screen (i.e it just shows the number) when a call is coming in - BUT when the recent call list is opened, the name appears as expected. The obviously worked prior to the move to the new device.

The same thing happens if the phone is locked or not. Contacts that have come in via MS Outlook work fine - i.e. the name is presented on the incoming call screen (instead of the number) AND also in the recent call list.

Help!