[1.15.2] Prefix group don't work

[chouuul]

This is my thutperms.json :

"groups": [
{
"name": "Fondateur",
"prefix": "[Fondateur]",
"suffix": "yyy",
"members": [
"4d4f770b-f62d-40bb-96e7-6423290*****"
],
"all": false,
"all_non_op": true,
"allowedCommands": [],
"bannedCommands": []
}
],

"******" is from me ^^

So I normaly have a prefix : [Fondateur]

But nop, I need to edit the player > 4d4f770b-f62d-40bb-96e7-642329******.json to have this prefix :(

[Thutmose]

it seems to be working on my end, I am not sure what the problem is for your side: