FYI
I have upgraded my v3001r to 6.5.22 from 6.0.63.
I use the ACD features and my main (Operator) ACD group is a calling group.
The CDR report shows all calls that didn't overflow out to another group were abandoned.
The NBX real time stats program and the acd stats page show accurate call records.
I upgraded the CAS and CDR to most recent versions.
Same issue.
Work around fix--- make ACD group a MIA group.
this fixed the problem. I did not try the other distribution methods.