Update: According to Polytron, the update has been pulled by Microsoft.

The long awaited Fez update has finally surfaced but with a huge caveat that'll spur people away. While the update has a huge list of fixes, Polytron updated the post saying after installing the patch, the save file will be seen as corrupted. The only current workaround is deleting your system cache but other than that, there is no fix. While you may want to put the blame on Polytron, Microsoft did pass it and didn't find this bug while testing so it sucks for all the parties involved. We'll keep you updated on whether this patch will be rectified in the future.

Source: Polytron