"Creating the user..." message remains stuck when creating a new local user on a local wiki

Steps to reproduce:

1. Create a new subwiki
2. Select the option "Only local users are available in the wiki"
3. Access the wiki
4. Select Administer wiki > Users
5. Create a new local user

Expected results: The user is created, creation message appears briefly.

Actual results: The user is created but the bottom message remains stuck to "Creating the user..." and the loading keeps spinning.

Note: After the page is refreshed the message disappears.