Meet InvalidJsonContentException error when provisioning user from IAS to SAP Jam Collaboration

We faced an error when provisioning user from IAS to SAP Jam Collaboration these days:

error=com.sap.security.iag.provisioning.mapping.exceptions.InvalidJsonContentException: Source path: $.userName is not available in content, but is required in defined system transformation Caused by: com.sap.security.iag.provisioning.mapping.MandatorySourcePathNotFoundException: Source path: $.userName is not available in content, but is required in defined system transformation Caused by: com.jayway.jsonpath.PathNotFoundException: No results for path: $['userName'],

But we did not changed any configurations and it worked several weeks ago. The transformations for the source is like this:

{
    "user": {
        "mappings": [
            {
                "sourcePath": "$",
                "targetPath": "$"
            },
            {
                "sourcePath": "$.id",
                "targetVariable": "entityIdSourceSystem"
            },
            {
                "sourcePath": "$.id",
                "targetPath": "$.userName"
            },
            {
                "targetPath": "$.id",
                "type": "remove"
            },
            {
                "targetPath": "$.companyRelationship",
                "type": "remove"
            },
            {
                "targetPath": "$.passwordStatus",
                "type": "remove"
            },
            {
                "targetPath": "$.sourceSystem",
                "type": "remove"
            },
            {
                "targetPath": "$.meta",
                "type": "remove"
            },
            {
                "targetPath": "$.mailVerified",
                "type": "remove"
            },
            {
                "targetPath": "$.groups[*].display",
                "type": "remove"
            },
            {
                "condition": "$.displayName EMPTY true",
                "targetPath": "$.displayName",
                "type": "remove"
            },
            {
                "sourcePath": "$.timeZone",
                "optional": true,
                "targetPath": "$.timezone"
            }
        ]
    },
    "group": {
        "ignore": true,
        "mappings": [
            {
                "sourcePath": "$.id",
                "targetVariable": "entityIdSourceSystem"
            },
            {
                "constant": "urn:ietf:params:scim:schemas:core:2.0:Group",
                "targetPath": "$.schemas[0]"
            },
            {
                "sourcePath": "$['urn:sap:cloud:scim:schemas:extension:custom:2.0:Group']['name']",
                "targetPath": "$.displayName"
            },
            {
                "sourcePath": "$.members",
                "preserveArrayWithSingleElement": true,
                "optional": true,
                "targetPath": "$.members"
            },
            {
                "constant": "urn:sap:cloud:scim:schemas:extension:custom:2.0:Group",
                "targetPath": "$.schemas[1]"
            },
            {
                "sourcePath": "$['urn:sap:cloud:scim:schemas:extension:custom:2.0:Group']['name']",
                "targetPath": "$['urn:sap:cloud:scim:schemas:extension:custom:2.0:Group']['name']"
            },
            {
                "sourcePath": "$['urn:sap:cloud:scim:schemas:extension:custom:2.0:Group']['decription']",
                "optional": true,
                "targetPath": "$['urn:sap:cloud:scim:schemas:extension:custom:2.0:Group']['decription']"
            }
        ]
    }
}

Could anyone help on this? Thank you!