I don't think there's a bug in the starhackit code. BUT...
I tried to use the patch code from app_user/profile and and re-use it in app_admin/users when logged in as Admin (and $npm run start:admin)
The patch appears to be working on the server when a new mocha test is run. The form on the client appears to be sending the patch request to the server. But the age does not update. Is the problem on the client or the server?
The fork is here: https://github.com/bigbadbrad/starhackit