The Ubuntu Kernel Team is unlike any other package maintenance team in the Ubuntu Project. We are also somewhat removed from the type of role of the upstream maintainers of the Linux Kernel.
The Ubuntu Kernel Team are a 'distribution-focused' team of engineers tasked with gathering the most stable patches submitted to the upstream tree for inclusion in a release every six months. This means that the Ubuntu Kernel Team are not doing the normal 'break-fix' work of other package maintainers. While we do, on occasion pull in pre-stable updates, we try to restrict this to critical subsystems that have proven stable by way of testing.
What this means to you is, should you file a bug, the Ubuntu Kernel Team are not necessarily the ones to fix the issue. It may be possible for us to see a fix that can be backported to your release from a later kernel, or perhaps your issue is configuration specific. Issues requiring code changes will be referred to the kernel.org bugzilla so that the upstream maintainers of the subsystems can get their fixes into the kernel by way of stable updates.