CraftingManager registers all crafting, even those things that are not yet implemented. You can craft any item even though the server doesn't support it.
Ex. Shulker Box, Armor Stand and etc.
It seems to me that this should be taken into account and players should not get access to those items that are not implemented.
specifically what items are you talking about
Please read issue before comment 0-0
I've considered doing something about this, but I didn't see it being worth the hassle. You can also obtain some un-implemented items from the creative inventory (for example spawn eggs, note block, redstone lamp, etc), so I don't consider this a relevant issue.
@dktapps
Hmm... However, these items have classes, perhaps you didn't understand me?

I understood you perfectly fine. Having a class doesn't automatically mean that it works. Like I said, I don't consider it worth the hassle filtering those out when half of the stuff that _does_ have known names doesn't work either.
For example, do Shulker Box

Let's say they are different colors, although I place only purple (It is normal for not implemented items)

(Quit and /gc to clean the chunks)

Now I can't place blocks next to the workbench, they just don't want to place there
And checking things would allow us to limit such things at the basic level.
My players have spoiled the whole map with this bug :DDD
So is there nothing from the aquatic update on the servers??
My Custom Crafting is effected by the removal of the CraftingEventPacket Data that was taken out due to UUID issues of some sort