From the https://www.tek-tips.com/threads/openscape-4000v10-cdr-local-unanswered-calls-are-missing-in-cdr.1828243/:
"Either SELG (SELT) THRGCON setting to N (Y means 'only through connected', so setting N collects more, not less), or ZAND CCD CDRRINGB to YES (cdr for ring back), or setting both...