When I was younger, I hated delays with a fury, because I was impatient. As I grew older and wiser, I realized that delays meant more time to work on a project, which oftentimes led to a better quality project. This seems to be the case with the SHIELD.
According to NVIDIA, the issue is with a third-party mechanical component. Both NVIDIA and the supplier are working hard to address the issue and to get the SHIELD up to expectations. It's definitely unfortunate for an issue to crop up at the last minute like this, but it doesn't look like we'll have to wait that long.