I think this has to do with rotation. When a custom modeled item isn't rotated at all in its GUI display setting than the shadow rendering bugs out and causes it to go dark. (I am also having this issue)
every tick
BronGhast
I think this has to do with rotation. When a custom modeled item isn't rotated at all in its GUI display setting than the shadow rendering bugs out and causes it to go dark. (I am also having this issue)