Thought I would update this in case anyone else runs into the same issue. After attempting to roll back to 4.30i, manually reprogramming the entire system, pulling the customers switch off their data network the problem persisted.

Samsung replaced the MCP with an MP20 and the problem disappeared. Seems that there are certain cases where an MCP doesn't like the upgrade to 4.42a. Samsung acknowledged that they have seen it in rare cases.