Actually, I just made a mistake. D'oh!
The recent Moose TV was of the Delta II (I don't remember if it was "heavy" or not).
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I just went off course when the question about the Delta IV flame/exhaust color came up.
Delta IV was launched a week or so earlier and I missed the live coverage. If Moose was working that one, he would have been pretty stressed since he monitors the performance (i.e. how much fuel and oxidizer left, speed, altitude, energy, etc.). So when the side boosters followed by the central core booster shut down a few seconds early and dropped away, he would have been watching the upper stage burns and levels and seen the inevitable 'run dry' situation.
-Fred Shecter NAR 20117