Any chance of a vid of that gate not doing its job so I can compare to mine doing it?

Usually these things are a mechanical bind of some sort.

Yep, I will do that tonight.  I've tried it with and without the wire part of the gate and different plungers too.

I actually suspect its the CPU board not holding the gate open long enough.  I emailed Dave (Ni-Wumph) and he is kindly looking into the matter for me.  He also suggested the sound loop may be a driver board issue which I will look into.