No, CBC has been a resounding success for both freight and passenger rakes. For freights it has resulted in increased and rake length and load capacity and for passenger trains, it has resulted in higher safety.
Coupling breakage can occur due to improper locking of the CBC knuckle or lack of quality in manufacturing. For CBC couplers, there is a single point of failure, which is the 'knuckle' in the coupler. Due to the above mentioned reasons, the knuckle can fail, causing the rake to part.
The staff have to be vigilant...
more... and IR has to ensure good manufacturing quality to avoid these problems.