Thank you for the QoS report, it is very helpful. You forgot the TCH mean duration time though… can you get this value for those 2 hours ?
In my opinion, this is an “artificial” issue, not a real problem. Either a counter problem, or a faulty software, somehow.
Maybe you should also check the TCH request for incoming HO and for call setup. You might measure TCH congestion due to incoming HO = 4%, while you’re having only 60 TCH requests for call setup.
Finally, in order to reduce the congestion, you could activate TCH QUEUING, and increase the timer T11. It might help…