Can't see caller name for a missed call with UC function

I am using the uc(calls, name) function as described here. But it shows only the caller number.

The function description says that it shows the name if it is available, but what needs to be done for it to be available?

I have the number in my contacts and KLWP has rights to access my contacts, so any ideas what is the problem?

Is the caller name also shown in the missed call notification?

Yes, the caller name is shown in the notification.