Any solution here, because I have the same problem.
I receive caller ID on incoming calls in the display area
Common Area Call Log Check is checked for all extensions
Call Log Answered Call says Both for all extensions
201st Call log in Common Area - Overwrite
21st Call Log in Personal Area - Overwrite
Caller ID Log Priority - Name
SLT Caller ID is not checked for any phone
CO Line Settings - Caller ID and Call Waiting Caller ID checked for all CO
Key programmed on left side of all KX-T7731 phones CID-C Selection and when pressed the screen always says OLD:000 NEW:000