We all know the rule never teach your girlfriend!
If you can't teach her how to use a Kahoona and it's safety options correctly, one of the nicest kites available, then she is going to miss out on skills required for all kites.
Sounds like you need to get your girlfriend professional lessons.
If there is no load on the Kahoona QR then you just un hook the chicken loop.
Pretty bloody obvious stuff.
It does not pack itself up either
If the leash is still attached then that depends on how the student has been advised to attach it.
The situations and rigging setup taught need to cover several options. And be applicable to most all brands.
Your specific location and requirements are quite unique and such a post headline "Best Kahoona - don't recommend for beginners" is way off the mark.
I'm guessing you gave the girlfriend a big fright and you tried to save face by blaming the gear.
Treat her to some professional lessons and she will be happy again & you will be the man.