iPad 9th Gen light sensor

I have around 90 iPads that will be distributed to employees. Around 50 have already been deployed. They were all 7th and 8th gen. The rest we just received are all 9th gen. All of the cases will be the exact same that are already deployed. The problem is that the cases seem to cover the light sensor on the 9th gen and dim the screen. This is not happening on the 7th and 8th gen's. I know its the light sensor because when I turn off auto brightness it does not dim the screens. The iPad cases we bought say they work with the 9th gen, and I guess they technically do fit. My question is: Did the placement of the light sensor change from the 8th gen to the 9th gen. Thanks