Hi freem,
Wow... I would never have guessed that those balls respawn. Still no respawn after 5 minutes, here. How many time does it takes?
If you're using the master branch of the git version, the boss was unfortunately broken due to scripting API changes not well handled by the developer (that would be me.)
and this was fixed yesterday.
If that's the case, could you try again after recompiling the latest version?
Best regards,