commands.scoreboard.players.tag.tagError doesn't have its translation file

I accidentally added an unintended curly bracket to a /scoreboard players tag command, and in the output it said 'commands.scoreboard.players.tag.tagError'
To check if it does have its translation file, i set up a tellraw command that would translate the output, but it did nothing.
Steps to reproduce:
1. Get yourself a command block

/give @p minecraft:command_block 1 0

2. Place it in your world

3. Put in this command:

/scoreboard players tag @e[type=Item] add (any tag name) {Item:{id:"minecraft:blaze_rod"}}}

The additional curly bracket in the end is for triggering the translation file, the tags can be other than {Item:...} and can be triggered on all entities.

4. Set the commandblock to Repeat mode, and to Always active, and if the button in the output is set to X change it to be O.
5. Exit the menu.
6. Drop a blaze rod.
7. Open the commandblock's menu once again.
8. Copy the translation in the output, (Ctrl+C/Strg+C/Cmd+C) but not the time.
9. Place an another commandblock, and open its menu.
10. Put in that command:

/tellraw @p {"translate":"(Paste the output, Ctrl+V/Strg+V/Cmd+V)","color:"red","bold":"true"}

and set it to be Always active
11. Exit the menu
12. The commandblock will say {color:red}*commands.scoreboard.players.tag.tagError*{color}
13. Delete the command, and type in this instead:

/tellraw @p {"translate":"subtitles.entity.generic.explode","color:"red","bold":"true"}

(those are the entries for the Explosion subtitle) Also, set it to Need redstone
14. Power the commandblock.
15. It will now say {color:red}*Explosion*{color} wich means, that the commands.scoreboard.players.tag.tagError output doesn't have the translation.
I have put the 'how i did that' in in a YouTube video, as the attachment is too big. https://youtu.be/_wcH7rVGLzU