It means that, before, the plan was for this bug to be fixed by the initial stable release of Ubuntu 11.04 Natty Narwhal. That was not going to happen (and didn't), so the plan was changed, for the bug to be fixed as an update to Ubuntu 11.04 Natty Narwhal.
It means that, before, the plan was for this bug to be fixed by the initial stable release of Ubuntu 11.04 Natty Narwhal. That was not going to happen (and didn't), so the plan was changed, for the bug to be fixed as an update to Ubuntu 11.04 Natty Narwhal.