Why does the category of goods change when exchanging orders between 1C and Bitrix?

Question

1C-Bitrix

1C - update 2018. Shop - Bitrix + crm.

Unloading of goods goes through one module (to the store). The exchange of orders goes through another (from crm).

When the exchange of orders is synchronized, the category id of the purchased goods (in the store) in 1C is overwritten and thrown to the root of the structure, the units of measurement also change (pieces for pieces, kg for kilograms).

How is it possible to solve the problem with resetting categories and changing units?