Hi, this seems odd to me but I don't have a ton of experience - we just bought a 128 6S to replace my wife's 16 GB iPhone 6 on 9.3.5. Oddly (I think) her new phone has 11.x downloaded but not installed. It's running 10.3.2. So the phone existed post iOS 11 but it only has 10.3.2 on it and not 10.3.3. In terms of timing this seems like an odd chain of events to me, is it a bit weird? I was expecting 11 to be installed but thankfully not.