When launching an app (with offline-allowed) online from the cache, there are two cases where behavior is broken compared to tiger.
1.) if using Basic Authentication, and you cancel password dialogs, app will not launch from the cache (try http://dispensable.east/BasicSecurity/minesweeper/minesweeper.jnlp)
2.) if host is not available, app will not launch.

both cases launched from cache in 1.5.0