First, I'm not an expert gyro pilot, but I just had some thoughts on this as I was learning to ROG my PT Gyro.

The reason my PT gyro was tipping over was that the rotor was not in autorotation. If the rotor is in autorotation and going across the ground slowly the center of lift is pretty much at the hub. If the rotor is spinning, but not in autorotation the blade advancing into the wind is making almost all the lift. Watch and see if the gyro dosen't always tips toward the retreating blade.