Brightness Slider Widget unresponsive/laggy when using internal graphics chip on Monterey

Describe the bug
After updating macOS from Mojave to Monterey, the brightness slider widget is not working properly anymore, but only when the internal graphics chip (Intel 2017 MacBook Pro) is in use. Visually, the slider will continue to react normally to tapping or sliding, but the display brightness simply won't change most of the time. If I slide around a lot it will actually change the brightness every few seconds or so, but it seems random and laggy. If I let go off the slider after changing it without the actual display brightness having changed, it will return to its previous (correct) position a few moments later.

All this does not happen when the discrete graphics chip is in use; the slider will function normally and properly then, as it always has.

All other methods of changing the laptop display's brightness continue to work fine: BTT Touch Bar buttons set to use display brightness actions, Apple's Touch Bar brightness buttons, Apple's Touch Bar brightness slider, even this Terminal command. No difference between internal and discrete GPU there. Only the brightness slider widget is affected. Also, no issues with the internal graphics chip in general.

This issue definitely began after the macOS update; I never had any issues with the slider before in years of use. I've tried reverting to an older BTT version which I had been using for a long time (3.756), but the issue remained.

I've restarted BTT, restarted my system etc. pp.

Any help would be greatly appreciated, as the brightness slider is the single most useful feature of the Touch Bar for me, and almost essential given the lack of physical buttons.

Affected input device (e.g. MacBook Trackpad, Magic Mouse/Trackpad, Touch Bar, etc.):
Touch Bar

Device information:

  • Type of Mac: 2017 MBP
  • macOS version: 12.6.1
  • BetterTouchTool version: 3.936