Is what happened with the center's director considered the forbidden discord that prevents good deeds from being raised (to Allah), and is it obligatory to seek him out despite my forgiving him and not knowing his whereabouts?

There is no religious obligation to speak with the center's manager to avoid forbidden abandonment unless there is a kinship or neighborly relationship; merely exchanging greetings is sufficient. A Muslim is not required to speak with every Muslim to avoid abandoning them. Giving greetings is commendable, not obligatory, and financial rights, if any, must be fulfilled. Forgiving a right earns reward for its owner.