If it were an all in one mix, like a bisquick, then yes, it containes shortening which can go rancid, and even if frozen can develop an off taste after too long in the freezer.
However, I am sure it would have been "safe" to eat..
If it were at MY house, I would have made a small batch, tasted it, and if OK used it..
In such a public setting, well one or two bad pancakes can ruin the word of mouth for years...