I have created custom field in requisition list form which is used in B2B
Created extension_attribute for it in the path etc/extension_attributes.xml
But when saving the form I am getting below error:

{
    "message": ""%fieldName" is not supported . Correct the field name and try again.",
    "parameters": {
        "fieldName": "DisclosureLevel"
    }
}

This is my extension_attributes.xml file

<extension_attributes for="MagentoRequisitionListApiDataRequisitionListInterface">
</extension_attributes>

declared attribute like below

<attribute code="disclosure_level" type="string"/>

Also created db_schema.xml

<table name="requisition_list" resource="default" engine="innodb" comment="Requisition List Table">
    <column xsi:type="varchar" name="disclosure_level" nullable="true" length="255" comment="Disclosure Level"/>
</table>

While logging I found this error is coming from MagentoFrameworkWebapiServiceInputProcessor.php

Line

$camelCaseProperty = SimpleDataObjectConverter::snakeCaseToUpperCamelCase($propertyName);

How this can be achieved please help me?