Changing Color Adjustments Sliders via Accessibility API do not update correctly

[latenitefilms]

Apple Feedback Assistant ID: FB12359669

THE PROBLEM:
When updating any of the new Final Cut Pro v10.6.6 Color Adjustments sliders via the macOS Accessibility API, whilst the slider does “physically” move, it doesn’t actually “update” the value in the rest of the Interface. For example, if I use Xcode’s Accessibility Inspector to change the value to -100, whilst the interface shows -100, the viewer doesn’t reflect this change. In the attached screenshot, you can see that I’ve used the Xcode Accessibility API to change the Exposure value to -100, but you can see that the blue image in the viewer is still very bright, whereas it should be much darker with -100 exposure. Clicking to a different clip and coming back will update the image.

WHAT I THINK IS GOING WRONG:
It doesn’t seem like Final Cut Pro is updating the AXSlider value when using the Accessibility API.

WHY THIS MATTERS:
This goes against the Apple Accessibility guidelines - changing the AXValue of an AXSlider, should correctly update the value in the application.

RELATED ISSUES:
See FB6151156

[latenitefilms]

Still broken in 10.6.7.