Hello folks,
I had the problem with a web app I use offline thanks to the cache manifest, but the ionicons never showed up when offline.
I found out it was because of the ionicons version in the URL referenced in the css, and I found this blog post confirming it and giving some solutions: http://developer.mobilecaddy.net/2014/12/offline-ionicons/.
I thought it would be nice to share this here, in case someone comes across the same problem and looks it up in the forum.
Cheers