Variations and the quotation system
When creating a quote for a customer and your products contain variations it's important to note that variations configured using the 'all variants' feature are not compatible with quotes.
What the all variants feature is
The all variants feature is a quick way of creating variations on a product where you don't need to specify a separate price, weight or sku code/stock quantity for your variations.
The all variants feature can either be used explicitly by you (when creating variations), as shown on the screenshot below:
Or can be used by default when you choose not to enter separate information for each variation:
i.e. by not ticking the box (indicated in the screenshot above) to enter separate prices, SKU codes or weights for the variations you're creating.
What you can do
The all variants feature skips a lot of the normal variation creation processes and for some technical reasons means that product variations using 'all variants' are not compatible with quotes.
If you want to use your product variations with quotes, the variations must be individually configured.
To do so, when creating variations make sure you tick the box to enter separate prices, SKU codes or weights for your variations and make sure that each variation combination has it's own row in the variations table (as shown in the screenshot below).
You don't have to enter separate information for each variation combination however, you can leave the SKU, price, weight ,stock and GTIN fields blank and each variation will inherit the information that's set for the product.