The video was good to see, it really shows how usable the feature is provided it doesn't happen 10 feet off the deck. Sorry to ask if it's already been asked - but are you running kerosene or deisel in these engines? What oil? Did you confirm your flameout issues were related only to the "too aggressive" acceleration schedule or was there something else going on that you were able to pin point and eliminate?
I've only had two flameouts in a turbine engine and it was a P-60SE early model that I had set for too aggressive of an acceleration schedule at 8500' density altitude. And both happened on the ground the same day during testing to see how the engine was acting before takeoff on this hot and high altitude day (that setting worked fine at sea level btw). After dialing the acceleration schedule back a bit it ran fine at 8500' DA too. A ground test will reveal this sort of failure mode with slam idle to full power thrust tests and rapid idle back tests. Too fast of an idle spool down schedule can also create this failure mode so deceleration is also a player in what I've learned.