Diffs to talk pages (such as users receive in email watchlist notifications) result in a loop when you try to open them with the Android app.
The new native Talk page display is great! I can follow a talk link from a watchlist email and see what someone said! It looks great!
However, if I open the diff link from such a watchlist email, it opens the 'open with' dialog, and if I choose the Android app, it immediately re-opens the 'open with' dialog, and I can engage in an endless cycle of trying and failing to view a diff using the app.