Postman Monitors fails to execute Pre-request Script and fails to read from Variables current value

My question: Postman Monitors fails to execute Pre-request Script and fails to read from Variables current value.
I have created a collection with POST and GET where I have used Pre-requested Script and set all other Params & Authorization with Variables.
However, Postman Monitor does not read the Prarams Variables’ current value and does not execute the Pre-requested Script.

Details (like screenshots):

//////////////// Pre-request Script:

const body = {
mode: “raw”,
raw: JSON.stringify({
“grantType”: pm.collectionVariables.get(“GRANT_TYPE”),
“username”: pm.collectionVariables.get(“USERNAME”),
“password”: pm.collectionVariables.get(“PASSWORD”),
“rememberMe”: true
}),
options: {
raw: {
language: “JSON”
}
}
}
pm.request.body.update(body);

////////////////////////////////// End Pre-request Script

Has anybody experienced similar issues and found a solution? Or please could anybody help me with how I can use the collection variables’ current values and pre-requested script through Postman Monitors for a collection runner

Many thanks for considering my request and I really appreciate any help you can provide.
Regards