The weapon comes with and empty rune slot, however you cannot slot a rune there.
I know you didn’t want unique weapon ruins to be extracted, but what about adding to an empty slot?
Is this intended? Because if it is, that’s pretty troll.
can you maybe elaborate the issue a bit more? not really self explanatory that screenshot. and i assume u meant to say “unable to slot rune”?
so u can not fill that last empty rune slot? does infusion work? or upgrading? i am sure more info would help investigate it.