Beginner. MPQ Editing. CustomData Savefile not recognised in hacked map

[lota7]

Hello,

I am new at MPQ Editing.

I've been watching tutorials and have chosen test on this fuflfilled hacked map by devoltz.
viewtopic.php?p=212211&hilit=heroic#p212211

This custom map has a customdata save function, so it remembers for next game.

Problem is, my hacked map, the customdata save cant be loaded / is not recognised as valid, so the saved progress didnt carry over.
After much searching code why my save didnt carry over,
I then decided to Open devoltz hacked map, copy his ENTIRE war3map.j, OPEN a fresh empty war3map.j file in Visual Studio Code, paste it in, save, put into MPQ, load map.
Then that map didnt work either?

Something I noted is that the file got bigger when I resaved...mind you I just copied the entire war3map.j from devoltz hacked file, and inputted it into a fresh war3map.j that was empty before pasting it in. And still it got bigger? Id it the program? Charset? I tried changing to JassCraft and do the paste, the file got a bit smaller than Studio did...but that too got error that my custom save couldnt get loaded.
Map and cheats run fine, it's just the load isnt recognised so the saved progress didnt carry over.
Could it be something with the way/app I save war3map.j?

I looked into the MPQ file and compared every file other than war3map.j and they were identical size to original map, so it's safe to say only war3map.j was altered.

What am I missing?