Here is what mine does, after automatically connecting to wifi at home or at work, and I sit the phone down. Sometime later I hear an email or a text come in, so I pick the phone up to find the wifi has turned itself off and 3G has turned on. I had a D1 for 2 years that never did that. Once on wifi it would stay there all day. The reason this is a problem for me is for the most part, I only use data over wifi. When they offered the 150 mb for $15 plan, I jumped on it. I have been on that data plan for about a year and have never went over. I never even got to 100 mb in a month until I got the X2. In 3 weeks since I got the X2 I have gone over the 150 mb, which tells me this thing is made to use more data.
I stopped by the Verizon store today and asked them if anybody else has reported this issue. They said they have never heard of this happening. They did a factory reset on my phone and told me to let them know if it happens again and they will give me a new phone. He said that he thinks there is a timer built into the phone that auto shuts the wifi off after a certain period of inactivity. I have tried the 'Keep wifi" app and it doesn't work. Any ideas?