"Not all product properties added to the cart are filled" - what's the problem?

Question

1C-Bitrix

Some products are not added to the cart, an error occurs: "Not all product properties added to the cart are filled." At the same time, in the component settings, there is a checkbox "Allow to add products to the cart that do not have all the characteristics filled in". What else could be the problem?
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PS I noticed this behavior: a $arResult['PRODUCT_PROPERTIES']property of the type "Binding to elements" or "List" is not added to the array if it is filled for this product. If not filled - in that array there are all its possible values.
For the "List" type property, everything works - including the "Allow to add products to the cart that do not have all the characteristics filled in" checkbox. For a property of type "Binding to elements"
Can anyone please explain the reason for this behavior.