Incoming SMS messages tend to get deleted immediately on my Galaxy S2. The original messages app does not cause any issues, but if I turn on hangouts it goes nits.
Edit: were talking about an unrooted galaxy s2 with the latest Samsung firmware. If I disable hangout sms feature everything is fine. Funny thing there was a big period of time when hangouts worked flawlessly. I guess the desire is to use hangouts for sms if possible.