For the first one, was the call disconnected by your own digression at the application level, or by the remote side?
I know in some cases, the value may not be populated correctly for GC SS7 variant in comparison to other protocol (ie ISDN, VOIP). So that may be ok.
As opposed to real reason like the second one would seem more legit giving a factor as congestion sent by the remote switch. Meaning it cant handle call right now.
Jeff