There's a need to explain how ODM AD is treating OU structure and decides what OUs will be created and what not.
ODM AD is only creating sub-OUs of the "mapped" OU as a hierarchy. And "mapping" is happening between each OU, specified in Stage, source OUs, to the target staging OU.
For example:
There's an source OU called "Main office users", that has 2 sub-OUs, "Accounting" and "IT".
This "Main office users" OU was specified in workflow Stage as a source OU.
After running that workflow, Write will create "Accounting" and "IT" OUs in the target under the staging OU.
"Main office users" OU will not be created.
Please note, that there's no "pick and choose" which sub-OUs will be created in the target. Once OU is "mapped" through the Stage, source OUs, all its sub-OUs will be created under the target staging OU.
Additionally, if source OU is empty or contains out of scope AD objects, it'll not be created as well.