When question and his answer were updated I saw the banner:
You can see that question has only one answer, but message says "answers".
- App Version: 126.96.36.199
- Device: iPad Air 2 (Wi-Fi)
- OS Version: Version 10.3.2 (Build 14F89)
This is more or less by design.
When the question hasn't changed, we can show "N new answers", "N answers edited" or "N new and edited answers."
When the question and answers have changed, there's only so much information we can cram in there and still fit on a 320pt wide phone.
"Question and answers updated" means the question has changed and the answers section has changed. This could be mean we have edited existing answers or added new ones. In either case, the question is in a lot of flux, so refreshing is probably a good idea. ;)