While the firmware updates always have to chance of screwing something up, I'm not having problems like this. My solar panel is working as advertised when it's warm enough and recordings happen properly.
It's possible that the positioning is failing to detect due to the way people move. Best detection for any PIR sensor is across the FOV, not directly at the camera. Post screenshots for suggestions.
* sorry, typing this on a mobile phone an it's hard to make links all pretty.
We are experiencing this same problem. Which makes these cameras pretty much worthless. I have a camera viewing my back patio and a camera that views my front porch and the county road in front. We went to leave the house yesterday. I went out the back door to put up my puppy. The back camera did not record this at all. Then we backed out our garage and left down the road and the camera did not record. Yet both cameras recorded when we came home. Also we see recordings of vehicles leaving out down the county road...but not coming back...and then leaving out again. So it appears the cameras are missing 20 to 50 percent of the time. These cameras are very expensive. This is a huge problem. I would send them back but I threw all the packaging away...we have only had them a couple of weeks and had planned on purchasing 5 more. Unless there is a fix we won't be purchasing anymore Arlo cameras