There are two things this camera can automatically adjust for exposure, the iris, and the video gain (AGC). And, like every other camera, they're only going to produce predictable results while filming a test card. Every real-life scene is going to have non-average results, and require non-average exposure. By the time you've fought with tweaking the automatic settings to get correct exposure, you may as well have set things manually, in the first place. And, with manual settings, they won't change as you pan the camera around. Automatic settings will change, as the average picture level changes, as they try to maintain the same average levels as beforehand, even though they're not appropriate to another shot.
e.g. If you were filming in a dark room, with a person highlighted in one spot, you'd manually set your exposure on them (presuming they were the point of interest), and as you panned around, or they moved around, the picture wouldn't change exposure levels. But, with auto-exposure, the camera would take an average reading, and when the person was in the scene, they'd be exposed to an average level, and as the person moved towards the edges of the frame, the overall average picture level would drop, so the iris would open up, to make the overall average of the picture the same level, you'd see the background get brighter, and the person get brighter, as if the lighting had been turned up. Then, if you panned back towards the person, or they walked back into frame, the iris would close down.
This camera's auto-iris is a measurement of the video signal through the lens, to adjust for an average level. There is a slight bias to ignore the very top of the frame, where bright lights and sky could influence the camera to close down the iris too much for the the rest of the shot.
Auto-iris just doesn't work unless your picture happens to have an average expose level, over-all. Scenes such as a person against a black, or white, background need full manual exposure control to get proper exposure.