I can't recreate this issue on PS 2017.1.1, Mac 10.11.6. Using a painting tool, Ctrl + Opt + drag left/right changes brush size. Ctrl + Opt + drag up/down changes brush hardness.
Sometimes we see other applications interfering with the modifier keys (Chrome and Chrome extensions come up regularly), and sometimes a Wacom driver does it. Is your driver up to date, or did you just update it?
Thanks for your comments. I updated photoshop about a week ago, but updated my Wacom driver yesterday. I think you're correct, it is probably the wacom driver update. I'll contact them about this issue, their customer support is excellent. Thanks.
I saw something similar yesterday on one of the forums. The latest Wacom update seems to have impacted the modifier keys. Wasn't quite what you're describing, but similar enough that it was worth mentioning. I'm glad you're looking into it further.