I'm trying to decide if my phone is defective or if other people are running into the same issues. I got the two sim (ordered direct from Microsoft US) unlocked version on at&t. I'm wondering if I am having issues because of the missing band 17 or other key at&t bands or if it's the phone. What I'm seeing with the phone is that most of the time it shows 1-3 bars on 4g. Sometimes 4 but when I wake it up it shows 1. Other at&t phones are getting 5 bars in the same spots in my house and never show no service like the 650 does. The signal seems to really jump around. I will place a test call when I have 1 bar and it then goes to 4 or 5. It's very odd. It also shows no service sometimes. I thought it was my touch so I got a case for it and the same issue happens. The data shows 4G most of the time. It will show LTE when I'm near a major part in the city. I run speed tests and all I can get is 5m down. Most of the time when I leave wifi the phone has issues switching over to the cell data. Airplane mode and back off seems to work. For a test I placed the same sim card into my Nexus 6P and it's got full bars, no issues, service is rock solid. As another test I also put a tmobile sim card in to the second slot to compare. It showed the same various signal results and even shows no signal more. Could the unlocked 650 be missing some bands that are used in my area or do I need to get a replacement or is it the current OS build (it's up to date). I really love the phone it's just really buggy with the signal. I have performed a hard reset on the phone and the same. Just wondering what others are seeing on a dual sim with at&t.