Reporting usernames to WP:UAA fails consistently

[tux3]

The User -> Report Username functionality seems to be broken. I've tried it twice to report promotional usernames with no effect.

I do not get any error message when submitting. I believe I also remember seeing a success in the system logs. But checking WP:UAA and my contribs, no submission was made.

The Report User functionality does work correctly, however. I'm using the latest version, compiled from Git.