Although I support the main message "update your header to a state or the art KDF", think you are not making the community a good service here.

Where is the indication that this was an attack against the KDF? For all we know they could have found a bug in the LUKS implementation.

Or much more realistically this was just an evil maid attack, or somebody got his password via "non-technical" means like filming him typing it in a cafe.