Helmet Lock?

[GoldOxide_imp]

After looking at mine, and yours again, it appears that yours is broken. It is missing a plastic piece that goes from the rear to where that curved part of the lock tab is. You can see where it broke off in your picture. That curved section of the metal tab goes into the plastic and thus prevents helmet removal. Well, except it is plastic and looks like it can be easily broken off.

Yeah, helmet locks has always been like some sort of rotten cheese. There is no point engineering them to be more durable than cutting a helmet strap.