[cbValidation 1.2.1] - Failed to validate existence of field

One time the following validation code was working fine. If cartId did not exist, I received an error message from validationResults.getAllErrors()

`

validation = wireBox.getInstance(“ValidationManager@cbvalidation”);

// Set validation rules
constraints = {
cartId = {
required=true, requiredMessage=“Missing {field}.”,
type=“numeric”, typeMessage=“Invalid {field}.”
}
};

// Validate incoming data
validationResults = validation.validate(
target=args,
fields=structKeyList(constraints),
constraints=constraints
);

// Dump
writeDump(validationResults.getAllErrors());

`

But today, I got an exception:

Type: GenericObject.InvalidKey
Messages: The key requested ‘CARTID’ does not exist in the collection The valid keys are field1, field2…

I am running the app on Lucee 4.5.4.017 final and ColdBox 4.2.0.

Any idea what might be wrong?

Thank you!