This morning, like most, I set up at a local field. It is located behind a middle school and this was my last chance to use this location before school starts up again. I first flew my Radian for three batteries worth and had no unexpected results. Successful launches and recoveries. With my P2V+, I did all that I usually do. I had my Phantom well away from everything. I had recently pulled the cover off and checked the condition of some mods I had made to ensure wires weren't chaffed by their original placement. All was pretty good. None of the foam materiel I had utilized had degraded. I have the newest motors and ESC's. I also did the DJI dance and used my wood table properly balanced and laptop to compare the various values and all were well within limits. Since my wife had placed my DJI case within 1' of our sub-woofer here in the house for our home theater setup, I felt the need to ensure the compass calibration and IMU Advanced Calibration was good. Both were. The IMU here in the house where I've always done it and the DJI dance in this field where I've cleared of all metal with my metal detector. As I said, NO metal was anywhere near where I did the DJI dance this morning. The moment I took off, with authority to get the bird off the ground and into my 10' hover for a HL point to be set, the P2V+ V3 suddenly went into RTH mode. How did I know this? It went to the preset 150' altitude I use for clearing the tall pine trees in my area. It then moved roughly 10m North and 25m West which was the LAST place I had set a good home lock point just two days ago. I'm quite confused since I had done a BTU reset and complete IMU calibration. Then the DJI dance within minutes of this flight. I did, of course, power down everything and restart after doing the last dance this morning. As the Quad went off to the previous HL point, I placed the TX into ATTI mode and flew it back. I did allow it to go to the last HL point first, where it came to a 150' hover since there was nothing at that altitude that would interfere with the flight path. As soon as it stabilized, I switched to ATTI mode and brought it right back to me despite the 20mph winds. I had plenty of battery power by the time I brought her back to me. Over 80%. This is the first time I've had an un-commanded flight occur. I'll have to keep looking into this, but wanted to know if anyone had experienced something of this type in the meantime. I flew her out of my backyard just 45 minutes ago and everything works just fine. I'm just confused as to what happened this morning a mere 750 meters from my home in this field.