No any crashes on save. Crashes in runtime when any UILabel present in scene and any gameObject.SetActive(false) (not necessary UILabel gameObject, just "any").
Linux and OSX builds only, Win32 + Win64 are OK, also I work in Win Editor, so don't know about mac editor issues if there are any.
To many "any" in the post spotted

---------------------------------------------------------------------------
Edit:
Also no dynamic fonts, using one of the NGUI demos atlas-based fonts for tests (Arimo20).