You also need to invalidate them when your TE is removed:
https://github.com/Draco18s/ReasonableRealism/blob/1.14.4/src/main/java/com/draco18s/harderores/entity/SifterTileEntity.java#L174-L179
popMatrix() is missing,
does rendering using addScheduledTask really work? Shouldnt you use one of the world render events for that? RenderWorldLastEvent together with a place to store the cables client side is what I would do.