Actually I thought I heard that from devs as well. Thanks for refreshing that.
Unfortunately it’s not a bug.
I guess its a purge-smith-recipe, but I am not sure. Some where going on about not every t4 smith having that recipe on advanced smith station.
Look here: Legendary Weapon Repair Kit? - #11 by DeadSpine
It is in the game. Some smiths can craft them.
It is in admin panel as well - using it repairs way up to full durability of the weapon.
On the other hand, those kits are meant to repair their tier or whatever is below that. This requires at least some featpoints-investment. I was unsure at first as well, but when I tried them, I instantly started to only use those to repair my stuff. Though I would agree that they are a little cheap to craft.
I think they are the most useful when playing in a clan, giving everyone a certain role, while everyone unlocks those repair kits. Maybe those kit-feats should get the double or even triple feat-point-cost?
But regarding this question wether being able to repair unknown weapons with a kit is a bug or not… It would be neat if a dev could take a look at this. Hopefully giving an answer - even if on the stream.