Why are products in a certain category not appearing when using the 'Add Ingredient' button whilst in a recipe?

Hi Tyrone,

Thanks for posting such a fantastic question!

This is restricted by settings under Property Administration

If you go to property > administration > property preferences > recipe > 'Allowed Segments for Recipe Ingredients' 

Here you will find the segments that categories come under that are allowed to be used when in a recipe.

Hope this helps :)

All the Best,

Joshua