I asked a question a few minutes ago (from the Android app, if it matters). An answer was provided, and within seconds of it being answered, the push notification registered on my phone that an answer has been provided.
Clicking on the notification loaded the Answers view for the question. However, no answer showed up. Refreshed - nothing. There was obviously some caching happening that was preventing the answer from being loaded. Interested in seeing how long it would take, I tried to refresh the answers on the phone every 5-10 seconds. In the end, it took the answer around 2.5 minutes to show up on the phone (counting from when the notification came through).
I would expect that when I get a notification of an answer and click through in the Android app, that the answer will be waiting for me when I get there. And if it is not, that manually refreshing will always pull the current data.