Step-by-step explanation:
Since the Austin OU (organization unit) is a descendant of the Texas OU, it naturally inherits the permissions from its parent/ancestors.
Any restriction (permissions removed) from the Texas OU will be inherited onto the Austin OU. This is exactly the intended purpose of organizing groups in OU's because all changes will automatically inherited within the OU without having to work down the tree.
This can be confirmed by checking with other cities to see if they too have the same restriction.
The proper way the request should have been done is to apply the changes to the most specific unit possible, be that OU's, groups, etc.