So I'm running into this weird issue right now. I'm using the latest version (fresh install) of Photoshop CC, along with a fresh install of my Wacom (Intuos Pro S) drivers.
However, when I'm holding the pen and hovering above my drawing area (with the brush tool active of course) using CTRL + OPTION to change the brush size doesn't work.
When I switch back to my Macbook's touchpad, it works fine.
I checked all of my tablet/pen settings (also tried mouse mode instead of pen mode) and couldn't find anything causing this.
Any advice is welcome!