Quick question, Im loading and setting a record like this

let recAuth = record.load({type: 'customrecord_id', id: id, isDynamic: false });
            recAuth.setValue('custrecord_field_id', authProfile.id);
            var custId = recAuth.save();

But I get this error

DeferredDynamicRecord.getValue: Missing a required argument: fieldId"

on the line that saves the record I tried with submitFields and with isDynamic = true and get the same error, any idea what could be?