Pen touch doesn't work, but it's button displays as active.

Start by updating your tablet drivers. I find that my pen stops working after an update if I don't have all of my drivers updated for my wacom tablet

However I also noticed that after this adobe update (to 19.0), ALL of my pressure sensitive brushes were gone!

I solved this by going in to the brushes menu, clicking on the gear icon, and selecting "Legacy Brushes", then saying yes to "restore legacy brushes".

I got all of my brushes back. I don't like how they're displayed in 19.0, but at least I have them again.

Hope that helps!!!

I believe the tools option bar Brush Control buttons are working correctly on my Windows Workstation with Photoshop CC 2018 and my Wacom tablet Pen.  Open a new document.  Select the Brush tool make sure the brush control button do not indicate the are active.   Open the Brush Setting panel and keep it visible.  Select a Hard Round brush and check the Brush Tip shape  setting are in the condition that all are unlocked and Shape Dynamics,  Transfer, and Build-up are not checked. 

You should now be able to use your Wacom pen on the option bar brush control buttons and see the brush setting are changing in the setting panel.

Please Identify you Software version,  Windows Version, Photoshop Version, Pen Device Driver version.  Also how you have configures Windows Pen and Touch,  Photoshop Pen Support, and your Pen Device driver Pen preferences for Photoshop.  Post a screen capture  showing what you mean by its buttons displaying as active.