Queueing is working only if there is a need to queue tch request = only if the cell is fully occupied.
Now, if there is TCH NA Congestion Rate > 0% and nuber of queued request = 0, there is a problem.
The maximum number of TCH queued in the whole BSC = 64. Perhaps you should reduce the queue size in the cells, so that the “64” can be equally shared among all cells.
I forgot the name of the parameter (Q_SIZE ?), what’s its value ?
Play soft with this parameter, don’t change it too much at a time.