Nice catch Bill !
I am wondering if your fireball spectrum is actually of the cooling afterglow after the remnant had passed on rather than the fireball at maximum, which would explain the change in the spectrum and the lack of OI/NI lines in the IR. If you look at the previous frames in the video where the main flaring took place, most of the fireball spectrum is saturated but the OI lines can be seen carrying on straight through (see attached). This would be analagous to this fireball spectrum published earlier this year (recorded in 2012) for example
figs 2 and 3