Hey @SlackHQ, what's been wrong with you these days? Why are you keeping sending me push notifications to Android for messages I've already seen on my desktop? Are you cosplaying HipChat (R.I.P.) ? 
Apologies for the trouble with push notifications on Android! It sounds like you're running into a known bug. We don't have an exact timeline on when this will be resolved, but we can assure you our engineers are working on it! 
