The news report suggests it was "Correctly Prepared" and that lots of places do them.

They are also claiming she had an "Adverse reaction" to it which I refuse to believe as it is completely inert and stomachs don't permeate themselves.

This suggests to me either that you are normally expected to wait for the nitrogen to boil off or that they put significantly too much in there.

I wonder if it was poured too gently and a layer of alcohol insulated the nitrogen preventing it from boiling off much in the way you can have superheated. layers in microwaved liquids.
I would imagine if you drank it, it would explosively boil and burst your stomach.