Comment 2 for bug 603192

I was able to repeat the steps, and agree with your assessment that the "reload" signal is getting delivered before the server has even registered its signal handlers.

I set it to medium, because it might expose the php code of an unsuspecting user until they restart the server.

One workaround would be to restart, rather than force-reload, in libapache2-mod-php5.postinst. Since we're changing the server in quite a fundamental way by loading new modules, this is might be a good idea to do on libapache2-mod-*, as it would leave apache in a much cleaner state, at the expense of maybe interrupting a few connections in massive virtual hosting situations.