This is a really frustrating bug that we are currently looking into to try to solve!
However, we have discovered that the OT isn't being deleted, but simply refusing to load. So you don't need to delete the ESV and re-download it, instead you can quit the app and force quit it and launch it again and the whole of the ESV should be there again!
More details about forcing an app to close is available at http://support.apple.com/kb/HT5137?viewlocale=en_US&locale=en_US
And we're hoping to have a new version of PocketSword out as soon as this issue is solved