Yes! Not only am I getting messages twice, sometimes hours later, sometimes MY messages are getting sent more than once. Again, sometimes hours later.
This is with a non iMessage user. Regular SMS.
However, I'm not sure it's an issue with the phone. I was having problems with SMS while using my Sprint Airave mini cell tower, texts all the sudden stopped sending. I unplugged it and let the phone connect to the regular Sprint tower then texts were working fine. I left the Airave disconnected.
Early this morning I noticed my signal strength wasn't what it normally is (I use the dB setting instead of signal 'dots' so I can tell what's going on better) To my surprise, I had an LTE signal. Weak, but it was there. They must have upgraded a tower. Had to have...usually I couldn't even get a 3G signal, hence why I had been using the Airave.
Blah blah basically I'm saying it could be something like that with you.. tower maintenance or upgrades. Cell phones act funny when they keep switching towers, at least on Sprint they do.