I have made a custom entity with the new addon system in v.1.8.0.8 Beta, and I told it to use the entity_change_color material on all parts except glass (that uses entity_alphatest). I also defined, in the behavior of the entity, that the entity is dyeable ("minecraft:is_dyeable"). The dyeing process works very well in game, the color does change, and, to me, it looks fine. But to someone else that connects via multiplayer the parts that are supposed to be dyed look black, no matter what color the entity currently has. This occurs on more devices, too, I had some friends test it out. It also happens with the entity_alphatest_change_color material