I think I've uncovered a serious valuation bug in Odoo 19 that could totally throw off your stock and accounting. I decided to run a quick test to see how it worked.
Practical Example:
I purchased a box of chocolate for $6. Each box contains 6 items, so the cost per item should be $1. Everything seemed okay when I first received the item; the valuation was a correct $6. But the second I issued the bill for the box, the system unexpectedly increased the cost of each item to almost double.