[Severe]Ichimonji Corsair Sword Bug

This sword makes it unable to do delves. Standing in light and equipping it causes darkness to infinitely stack on you until death. After taking it off, stepping back into the light is working as intended. But currently, doesn't work whilst inside any delve. Tried on multiple delves starting at depth 2.

Two screenshots below. 1st is with it on, and the stacks of darkness still going up. 2nd is with it off and the stacks gone.