So I keep getting a caution symbol next to certain brush settings for no apparent reason. The latest of Wacom's awful drivers are installed (and uninstalled, and reinstalled, 3-4 times) and I still get this little error thing, seemingly randomly. Can anyone help me out here?
What operating system are you using?
What version of Photoshop?
Which API are you using for pen pressure?
Assuming Windows and CC2018, you should be able to get away using Windows Ink, which seems to be working better than with earlier versions. Make sure it is checked in the Mapping tab (I don't use it so it is turned off)
If you still don't get on, and the intermittent nature of your issue sounds like you might be better with WinTab. So turn off Windows Ink, and follow the advice in this thread. Note that the path should be changed to CC 2018