Unable to get children categories when use the option "Use Flat Catalog Category" set to "Yes"

[dev-venkatesh]

Steps to reproduce

Login as admin
Go To "System" -> "Configuration" -> "Catalog" -> "Frontend" -> "Use Flat Catalog Category" and please set to "Yes".
Reindex the "Category Flat Data" option and try to run the below code.

$childCategories = Mage::getModel('catalog/category')->load($anyCatID)->getChildrenCategories()

It will not give any child categories and if you change the above option to "No" you will get all the sub-categories;

[sreichel]

Note for me ... https://magento.stackexchange.com/a/58450/46249

I'll test it later.