Not a bug Can't insert option into third slot

[Ura11]

I do everything as it should, I press the insert button, and nothing happens

 

[Manijak]

Please tell us from where you got that item as drop,and when did you drop it.

 

[stevechan88]

I have the same issue , can't proceed to item option adding.

 

[ValieL]

That's the case for every dropped equipment with an extended third slot (the ones with a plus sign on its third slot). But if it doesn't have that plus sign on the third slot, there is no problem with adding an option to the item at all. Unfortunately, I don't think a dropped equipment with a legendary craft will ever drop with a non-extended third slot. At least, I haven't had such an experience.
I also asked in-game why I can't add a third option to an item like the one in the picture and someone answered that I have to upgrade the item to +20 first before I can add a third option. I don't know if it's true though.

 

[Cykros]

This were old and bugged items from a previous lottery.
To be able to use this items and add the slots you first need to remove all slots with the slot option remover.