If you build a Titanium app that uses either JSS and/or i18n, then open the Xcode project and build for device, it does not regenerate the stylesheet.plist or i18n lproj directories. The old 2.1.4.GA iOS builder.py does generate the i18n files during the pre-compile phase, but doesn't appear to generate the stylesheet.plist, thus JSS probably didn't work before either.
Need to move those two generation steps into the pre-compile phase. Also double check that this doesn't break anything. There's a bit of an order to which events need to happen.