Json formatting not working after SP List update

Question

Hey guys, after a recent update to sharepoint lists my json formatting code stopped working as expected, cant figure out why.

Please notice the images bellow to see the diference.

Before:

After:

Here is the code

{

"$schema": "https://developer.microsoft.com/json-schemas/sp/v2/row-formatting.schema.json",

"groupProps": {

"headerFormatter": {

"elmType": "div",

"style": {

"flex-direction": "row"

},

"children": [

{

"elmType": "div",

"style": {

"padding": "4px 8px 5px 8px",

"border-radius": "6px",

"font-weight": "500"

},

"attributes": {

"class": {

"operator": "+",

"operands": [

"ms-bgColor-themePrimary ",

"ms-fontColor-white"

]

}

},

"children": [

{

"elmType": "span",

"style": {

"padding-right": "6px",

"padding-top": "2px"

}

},

{

"elmType": "div",

"style": {

"display": "inline-flex",

"padding-right": "9px"

},

"children": [

{

"elmType": "div",

"style": {

"padding-left": "5px"

},

"attributes": {

"class": "ms-fontWeight-normal"

},

"txtContent": "@group.fieldData"

}

]

}

]

}

]

}

}

}

Appreciate all the help