Brightness widget not maxing out

Description:
The brightness slider widget on Touch bar appears to go up to about 90%. This actually represents maximum screen brightness. When you drag the slider to max, it stays there for a second, before jumping back to 90%. The real brightness of the screen doesn't change during that action.

I've tried deleting it and putting in a default brightness slider widget, same issue. This doesn't happen with the volume slider widget.

Affected input device: Touch Bar

Screenshot:

Device information:

  • Type of Mac: MacBook Pro 15-inch, 2018 (Radeon Pro 560X)
  • macOS version: 10.14.1
  • BetterTouchTool version: 2.660

GIF of bug:
Touchbar%20problem

The BTTPreset file:
KISS Bar Modified.bttpreset (404.2 KB)