Fetching a node beforehand ruins ordering of collections

Two documents: Category and Subcategory
Category has $subcategories as a PHPCRODM\Children

If Category A has 3 subcategories B1 B2 B3.

If A's subcategories are fetched we would receive them in the following order: B1 B2 B3.

Now if however we fetched the B2 node using the DocumentManager at an earlier line and then fetched the subcategories of A, we would receive them in the following order:
B2 B1 B3