Explanation of the video (and the bug):

On the right, the purple command block will add a point to all items with the name "1".
(scoreboard players set @e[type=item,nbt=\{Item:{tag:{display:{Name:"1"}}}}] test 1)

And the center command block will give me a diamond with the name "1"
(give @p minecraft:diamond{display:{Name:"1"}} 1)

The purple block perfectly detects the diamond awarded by the center's command block; but, when I put a diamond from the inventory on an anvil and name it "1", it does not detect it anymore.

This happens because in the NBT Tags of the diamond awarded by the command block, you can see: {Name:"1"}, while in the renamed diamond you can see: {Name: "

Thanks to this, the purple command block no longer detects the renamed item.