@QMcKay I recently reviewed it and I’m pretty sure there is no bug here. quantity is an optional field in graphql and by default you shouldn’t set a value so it gets processed as 1 by default. If you set specifically 1 or any other value it processed as quantity for regular products and price for zero priced products. In next update we’ll also have a setting called “enforceQuantity”. When set to true quantity parameter is always set to quantity for all products.
Edit: Here we have a related post SambaPOS 5.2.11 Beta Release