Can't add user to child department in Zoho People

Can't add user to child department in Zoho People

I have entered our organization department structure, which includes Parent/Child departments, in Zoho People. When attempting to assign Users to a Department the only options are Parent Departments. The Child Departments do not populate as available options.

While investigating I noticed that the settings for the Department and Designation forms seem to be switched. See pictures attached. I don't know if this is related but it certainly points to some sort of issue.

As I haven't changed these forms, it must have happened when People was installed/activated in our Zoho One account.

Can anyone advise on correcting this issue?