Copy&Paste Gadget and Exchange tool create Domum Ornamentum blocks that crash your client when you interact with them.

For me it was Red Concrete Stairs, for my wife it was Stripped Spruce fences i believe

To Reproduce: Craft architect's cutter and use it to turn a red concrete block into a stair block, use the copy and paste gadget to copy and paste it and it turns into an Oak Wood looking stairs, the moment you touch this block in any way your client crashes.
(Had to use /fill command to get rid of it)