There is a problem if you use 0 as a index in a table in JSON.
LUA tables starts with index 1 and PHP from the backend start with 0.
There is conversion code so the indexes are correct but it might result unintended results because PHP autoconverts strings to integers.
If you index with a "0" string in JSON it will be converted to 0 int in PHP and the code that fixes indexes will be triggers and you will get a ordered list
Look at the examples below. There will be no fix because it it hard to do in PHP for a unusual case and it can be fixed with different config format.
JSON config followed by lua Print of the same data