Following a conversation and some debugging with Stéphane and James, the conclusion is that this is a bug in upstart which is failing to re-exec/reload itself and so doesn't see php-fpm upstart job.
Following a conversation and some debugging with Stéphane and James, the conclusion is that this is a bug in upstart which is failing to re-exec/reload itself and so doesn't see php-fpm upstart job.