It closes the forum fine... and then fires the exec command.
However, then the system has to wait for the exec command to send an all clear... which could be 10 minutes down the line, since mysqldumps can take a while. However, by then, the php script has been disconnected from the server and the open forum command never gets fired.
Is there some way around this? I thought the new XF cron system was supposed to handle stuff like this.