My sympathies. I had an issue with a FormitAutoResponder hook that fired 7 times every time on my sandbox server and the exact same code fired the required once on the dev and live servers (all running same Revo, but different PHP/MySQL and possibly OS as well. There comes a point where you stop worrying why something does/doesn’t work and simply go with what does work.
Writer > E-consultant > MODx developer || Salesforce || modx 2.x || PHP 5.2.13 || MySQL client 5.0.86