No specific knowledge of the A330, but I was directly involved in wind tunnel testing during the investigation of the Lauda 767 crash (after a reverser deployed in-flight).
During that testing, with the reverser deployed, the airflow and lift was destroyed over a large portion of the wing. On a swept wing, I'd expect that sort of airflow disruption with T/R deployment to result in a significant pitch down - not pitch up - moment.
I suspect ahramin and Chris Scott are correct that it has to do with the associated spoiler deployment, not the T/R.