Hi Bambang,
Do not be quick to lable your liner and Kockarden as wrong, one thing we have learned here is that nothing was standard, My liner is also fixed with prongs, the liner is very weak and thin, it this helmet was to be worn, the e=wearer would have to make it stronger in some way, I would guess that yours was worn and mine was not.
I think we are all looking forward to a new youngest member of the forum.
Gus