Exposure sliders unresponsive in mobile cc

I shoot cheer competitions and sync 2000 or more images in a collection. currently  I have around 12000 images across 3 collections on my iPad Pro 10.5. For most but not all images, the Light group sliders are unresponsive. Moving exposure +- 5 has no effect on the images just like the other sliders in the group. The only way I can adjust expose is with the curves. The other groups appear to work, just Light appears defective.

the images were loaded from Lightroom Classic CC and synced to mobile. I need help!

BTW, smaller collections don’t have this problem.

Ben