Photoshop :: Wacom Cintiq 24HD / CS6 64bit (Windows 7 64bit) Brush Pressure Sensitivity Often Fails

In Photoshop CS6 (64bit), when using the brush tool (with a brush with pressure sensitivity activated), I quite often get a line drawn at the max width selected, as if there was no pressure sensitivity. Everything goes back to normal after I start drawing another line, and happens again after a few lines. It's quite random.  
 
I don't have this problem in any other software (Illustrator CS6 64bit, Painter XII, Sketchbook Pro, Zbrush, ...). I have already checked and I've found some other users on other forums with the same problem.

One example, with a picture of the problem: [URL] Another one, exact same problem: [URL] Some of those users seem to have solved their problem by installing an old driver (6.1.5r3), but they had that problem with Intuos TABLETS in the first place, not a Cintiq 24HD... I have tried that, but unfortunately the driver is not compatible with the Cintiq 24HD.
  
To test this out: I've been able to reproduce the problem 90% of the times I've tried. if I keep the pen at 1 inch from the display so that it's still recognized by the screen but it's not drawing, then wiggle it a bit, and then I slowly move to the screen and tap it (as if I was starting a line with very low pressure), the problem appears and it makes a large dot, as if there was no pressure sensitivity. As I said the test doesn't work every time, but almost.
  
This is an image of what happens when I try and make dots in Photoshop. These are done trying to push the pen with the same (low) pressure. The big ones are from when the issue appears: [URL] 
 
I have tried the pressure test in the Wacom utility software and it seems to work fine, it never jump to full even when I try the method I've just described. In the diagnostic page of the Wacom utility software the pressure is always correct, even when in Photoshop there's the brush sensitivity issue.
 
note: I've already tried to completely re-install my computer + the Adobe software + the lastest wacom driver for my Cintiq 24HD, and the problem is still the same.