/summon /give Item +NBT

When you run this command:

/summon Item -522 65 -1071 {Item:{id:command_block,Count:1,tag:{BlockEntityTag:{Command:/clone -525 81 -1008 -525 81 -1008 -517 60 -1062 replace}}}}

This just summons a command block with custom NBT tags.
*This happens at giving items and at other items with custom NBT tags too

The command block item doesn't show the purple "+NBT"