I have encounter the same problem using an iPhone 13.
VoiceOver quick settings toggle for Image Descriptions does not work on iPad
On iPad, if you have the Image Descriptions toggle in the VoiceOver quick settings panel, the toggle does not work.
It always says it is switched on, and selecting it has no affect.
Steps to reproduce
Ensure that the Image Descriptions option is included in the VoiceOver quick settings panel.
to do this, go to settings>Accessibility>VoiceOver>Quick Settings, and make sure it is selected.
Now, from any location on the iPad, open the quick settings panel. This can be done by default with a two finger quadruple tap.
Navigate to Image Descriptions and double-tap on it to toggle it.
Bug First Encountered
Device(s) bug has been encountered on
How often the bug occurs
Add the Describe Images option to the VoiceOver rotor instead.