Ok in MHF i have these ruststones and i used to offline method of changing them from odd weapons such as iron lance to +knight lance to rusted lance
but whenever i get a great sword rust stone which is what ive been trying to get out of all the rusted weapons it will never turn into a rusted great sword, it just stays at iron sword and never changes no matter how many times i do missions to reset the weapon.

Can anyone help explain why this is happening to just the great sword and not to any of the other weapons i already have a rusted version of all the other class weapons, gun, sns, lance , hammer.

I just keep doing quests and more quests to see if the items sets will change, some of them do such as the hammers they got to +war hammers but the lance and gun and the great sword wont change and i haven't seen any of them turn into a rusted version yet, is there like a bug if i have so many ruststones that it wont give you a rusted weapon or something?

Ill just keep at the quests maybe it just takes along time if i have alot of stones or something, kthxbye