Hi,

When using CTRL+Middle Mouse Button in single player while looking at a command block, you receive an item in your inventory which is a command block + the NBT data.

When you place this block, it should have the command already inserted however when you do this in multiplayer while running spigot the data is not copied and on placing the block, there is no command already in the block.

This does however work for chests and there is no issue.

Thanks. Very small issue however this is large impacts on my server when using a lot of command blocks.