I've noticed a possible bug on the software of a Nokia 6021:
problem: Call register caches old numbers:
way to reproduce:
1: Save a phone number into the phone's memory
2: Call this number (by accessing the contacts list)
3: Change the number in your phone memory
4: Call this number (by accessing the contacts list)
Notice that now the old number is called instead of the new!!
5: Clear your call register.
6: Call the number (by accessing the contacts list)
Notice that now the new number is called.
Seems to me that the number is cached in the call register instead of referencing to the phone's memory phone numbers...