How to set up auto-substitution of item property values ​​after exchange with 1s and BUS?

Question

1C-Bitrix

Configuration 1C: UT
Configuration version 1C: Trade management, edition 11 (11.3.2.157)
Version of the integration module on the side 1C: Online store + 1 C (6.0.3.4)
After the exchange, the property values ​​are not automatically substituted, although they can be selected from the drop-down list on the product edit page.
For example:
Loading properties for five lights; one of the properties was "color"; the values ​​of this property are set to automatic only for three out of five lamps;
There were no regularities between properties and values ​​that are not automatically substituted. for one product from the product category, the value of the property can be automatically substituted, and for another product with the same property and even with the same value (the value may differ), this value cannot be automatically substituted.
The same situation is with the loading of a new nomenclature, the property values ​​may either not be substituted at all or substituted selectively.
What could be the problem? Is there any concrete way to force Bitrix to substitute values?

Answer 1

Only strings and numbers are unloaded concretely.
From my experience (I serve the exchange from the side of the site), if we are talking about a list and its values, the value IDs must be registered in 1C for correct unloading (similar to a bunch of products and sections by XML_ID).
If possible, prepare everything on the side of the site, raise the backup 1C and upload from the site there. And look how they unloaded.
To link some tricky properties, store strings and numbers in 1C, upload them to the site as a technical (intermediate) property, and link it to the “finish” property on an event.