I was once bumped off a CA flight ex-LHR due to overbooking. Not only did they rebook me on CX to get me home earlier than scheduled, flying direct instead of transiting at PEK, they offered monetary compensation on top of that.

When these incidents occur, I always request the airline to provide an official letter acknowledging the delay and the reason so I can claim travel insurance. Seems your delay may have been tech-related.