Empty file for bundles assets

We're using Cassette 2.0 and every now and then, the bundled assets in Cassette return an empty file. We're seeing this issue at multiple clients. We need to 'touch' a javascript or stylesheet in order to force cassette to create a new bundle. We have no idea why this is happening, but this is a serious issue.

These posts in the mailing list are similar to the problem we're having:
https://groups.google.com/forum/#!searchin/cassette/empty$20file/cassette/Kj0NHKwVpE8/crI4xe0yIkIJ
https://groups.google.com/forum/#!searchin/cassette/empty$20file/cassette/k3L7lLWtxGk/mld_UekcgR8J