Do you agree that the system must have kicked in?
No, it did not kick in by design.
If you fly an 'old lady with cables' nobody is pushing throttle for you, you must do it.
If you fly with AT it is your basic duty to monitor what AT is doing - if it is not doing what's supposed to do (say it is broken or failed or computer failed, etc) you must do it manually. Pilots must be able to handle adverse scenarios, if a pilot is surprised that AT did not do something for him and he crashed - that's epitome of stupidity and dereliction of duty. Reagan used to say during nuclear arms negotiation with USSR his famous "trust and verify", it applies to flying too.