When using the import/export feature in Prismic, it's worth being aware that document ids (which are used as filenames) are case-sensitive, and very often the only difference between two ids will be a different case letter. Being unaware of this has caused us all sorts of issues recently and I'm suggesting that it would be useful to make this clear in the documentation.
For anybody wondering how we solved this problem, we simply created a case-sensitive disk image that we export to and import from.