REST API /nodes/{noderef}/children does not fire OnCreateChildAssociationRuleTrigger so folder rule is not run.

Problem Description:
 
When calling the POST /nodes/{noderef}/children REST API to create new content in a folder, the OnCreateChildAssociationRuleTrigger is not fired even though the content is created in the target folder and there is an association created between the folder and the content.
 
If using the POST /nodes/{noderef}/move REST API to move content into the target folder, the OnCreateChildAssociationRuleTrigger is fired and the expected Rule is fired.

Steps to Reproduce:
 
1/. Install OOTB ACS v5.2.6.2
2/. As 'admin' create a site 'Rules-Site', add 2 folders 'RulesTest' and 'Testfiles'.
3/. Create a new text document in 'testfiles' called 'testdoc'.
4/. Create a new Rule on the 'RulesTest' folder called 'Rule1'.
Description:
 - Active (yes)
 - Run in background (no)
 - Rule applied to subfolders (no)
When: Items are created or enter this folder
If all criteria are met: All Items
Perform Action: Add 'Geographic' aspect
5/. Capture noderefs for testing:
 - testdoc: b6e59fe0-b5e1-4efa-92fe-28b110695ac3
 - Rulestest: 461d9b6c-352a-4c6b-8848-a532b4bf70bb
6/. Call the REST API:
 

http://host:port/alfresco/api/-default-/public/alfresco/versions/1/nodes/461d9b6c-352a-4c6b-8848-a532b4bf70bb/children?include=properties 

{ 
"name": "1111111111111", 
"nodeType": "cm:content" 
}

 
7/. Call the REST API:
 

http://host:port/alfresco/api/-default-/public/alfresco/versions/1/nodes/b6e59fe0-b5e1-4efa-92fe-28b110695ac3/move?include=properties 

{ 
"targetParentId": "461d9b6c-352a-4c6b-8848-a532b4b" 
}

 
Observed Behaviour:
 
There are 2 documents in RulesTest - 'testdoc' and '1111111111111'.  'testdoc' has the Geographic Aspect applied but '1111111111111' does not.
 
Expected Behaviour:
There are 2 documents in RulesTest.  The Geographic aspect should be applied to both documents per the Folder Rule.