[ChildNodeRelations] ChildNodeRelations of category is empty while it has more than one sub category

Description

Precondition: Install FindCommerce to a QuickSilver site

Steps to reproduce

1. Go to CatalogUI. Make sure that catalog Fashion has more than one available language. Example: English and Svenska are available.
2. Clear the index then run the indexing job.
3. Select Fashion and create a category name CategoryA. Then publish it
4. Select CategoryA then create a category name SubNodeA. Then publish it
5. Go to Find >Overview >Explore. Search by keyword CategoryA.
6. Find tag ChildNodeRelations in details of CategoryA.
Observed: ChildNodeRelations contains SubNodeA (good)
7. Go to CatalogUI. Then select CategoryA and create a category named SubNodeB. Publish it.
8. Go to Find >Overview >Explore. Search by keyword CategoryA.
9. Find tag ChildNodeRelations in details of CategoryA

Expected:
ChildNodeRelations contains SubNodeA and SubNodeB

Observed:
ChildNodeRelations is []