Brightness Slider does not update on touch gestures & original touchbar icons

Hi, to get rid of the "x" and just for learing i tried to rebuild the Control Strip. I added an group for the volume slider where i can controll it with a touchgesture what works but when i did it the same way for the brightness slider the brightness changed but the slider updates really slow or stuck at his position is this an known issue or is there a way to fix this?

And is there a way to get the original touchbar icon-set?