Just a thought. What happens if you disable the service from being polled automatically so you don’t get many false alerts
and set up a bash script in cron to manually run poller for that service device?
./check-services.php -h 203
203 is the ID of the device. You can try adding -d flag to see the debug output while testing.
Not sure if this works as you would expect but it may be worth giving a shot.