iPhone not saving exposure edits

After editing a photo on my iPhone and then clicking Done, my iPhone reverts back to an underexposed picture. It is like the screen is dimming down after I close the edit screen. When I click back on the edit photo button, the picture brightens up again to the better-exposed version.

If I make changes to the exposure manually (not using the Auto feature), it will also dim the photo but will retain some of the changes (for example, when I push the exposure all the way up, it saves an overexposed version, but not "as" overexposed as it showed on the edit screen).

Other edits like cropping, filters, etc. seem to work. But also dim / lower exposure when I close the edit screen.