If you have cc 2017 updated, Can you test if it happens the same for you?
Is it possible to go back to an earlier update?
Does this happen every time?
The reason I ask is that I tried to replicate your issue in CC2017.0.1 and sure enough, although the opacity override would turn on and off - the size override turned on shape dynamics but would not turn it off again.
I then went to 2015.5 and got the same , then I went to CS6 which appeared to work correctly. So I came back to CC2015.5 and CC2017.0.1 and both are now working correctly. I have not been able to bring on the problem again.
Before raising as a bug I would like to see what might be triggering/curing this. Anyone else have any ideas?
"Does this happen every time?"
No, Recently I noticed that the bug appeared when I frequently changed brush by activating or deactivating the pressure options ... I do not know precisely it's weird...
And when I restart Photoshop, the bug is not present on all brush. (For a time)
How do you go back to previous versions?
"So I came back to CC2015.5 and CC2017.0.1 and both are now working correctly"
Now it works for you without reasons ? Just after testing with cs6 ?
thanks for your answer
Probably more accurate to say - I saw the problem - it disappeared and I can't get it back (in any version) . Sounds like a bug - but I don't think going back to an older version will help - I also saw it in CC2015.5 this morning.
If you do want to install an older version (you can have several versions installed at the same time, as I have here) go to the CC desktop app, and under Find Additional Apps - click on Previous Version (Note this is different to the Previous Versions block which shows you different versions you have already installed.
Then click on Install and select the version you want