Certainly if the boiled quinoa has too much moisture, that could cause more of a mold problem.

On the other hand, expecting home-made baking to last for ever is not realistic.

Store-bought baked goods are full of preservatives, so we get used to crappy food products with a long shelf life.

Rather than drying the quinoa in the oven, you might be able to cook it with less water.

Or how about adding quinoa flour to your banana bread?

As for the flute like symptoms you describe, they could possibly indicate an allergy.

The only way to know for sure it to notice if you get a similar reaction every time you eat a particular food.