Spotlight cam pro battery with solar panel not charging correctly- does it charge one battery at a time?

HI, I just replaced an old Spotlight Cam Battery with Solar Panel charging with a SpotLight Cam Pro. After many headaches, (I had to get a dongle to go from plug in to USB C and I had to get a different panel for the back of the camera to take the USB C), it was finally set up to the solar panel. At least, that's what the app says, except that instead of the battery charge levels going up, they were going down. I live in Las Vegas, so direct sunlight isn't an issue. I rebooted the camera, and nothing. I then hard reset the camera and that made the app say that it was connected to solar but not charging. I then unplugged the camera from the USB C, removed the batteries and began charging the batteries. The app was still saying the camera was attached to solar when it was in my hand without any batteries in it. I then removed the camera from the app and, hard reset the camera and re-installed it. I had to hard reset the camera 3 times before it properly showed the solar panel being connected and charging. Now this is my question. It's showing that the right battery (Battery #1) went up from 89% to 91% quickly. The left battery (Battery #2) has remained at 88%. Does the right battery (#1) have to fully charge before the left battery (#2) starts to charge, or should both batteries slowly be increasing in charge?