Eevery now and then (I'd say a minute or two of usage) when I use my Bamboo CTH-670 in Ubuntu, it happens that when I raise my pen from a press the "release" isn't recognised. Instead, the pen stays in this continuous drag'n'drop mode while I'm moving it (without me doing any more pressing, just moving) which is very problematic - it rearanges my windows, changes the objects I am working on and it's not that easy to get it back to normal. Usually after I press the pen down a couple more times it does return to a normal state, but this recurrent behaviour is very unfortunate.
Whenever the pen is raised, no matter what I was doing or how high or fast I raise it - it must switch into a "non-pressed" mode.
I am using Ubuntu 12.04.1 LTS and the wacom drivers I acquired through the normal instructions (though they weren't in the repo, I think I had to add some PPA).
$ dpkg -s xserver-xorg-input-wacom | grep Version
If you require some additional information or some log files, just let me know.