Camera raw can not erase brush

Hi,

Since the last update of camera raw 11.4.1 or the instalation of imac Catalina, both same day.  When i use the camera raw brush to apply a effect like enhance a area, i can erase what i just painted. When i click on erase it switch back to paint.

I use a imac up to date and all my adobe software are up to date to

thanks for help