devtrackers.gg
The dragon kiteshield drop rate is honestly one of my favourite conspiracies in RS. There's no way it's 1/128 or not bugged for some people.
I saw your comment and decided to check the code as it piqued my curiosity.
So it turns out the rates listed on the Wiki (that reference a thread on the RuneScape forums) are actually incorrect.
The drop rates are X/250 and not X/128. This means that the drop rate for the Dragon Kiteshield is actually 1/250.
I'll look to get the forum thread updated and make the Wiki aware of it.