Some of the user comments here were helpful. Wacom was not so helpful. I have found, like others, that the modifier keys on the EK remote instantly crash the pen and you need to reboot. specifically when I map the lower right two keys to zoom in and zoom out, the pen crashes every time.
I talked to support in the US today after weeks of trying to get through. First, I was told that if I can't wait on the phone for hours, that I could use the online chat, and that would work better for me as their phone lines have been very busy. So after discovering some new information I went back to the website and looked for the online support chat. There is none. So why the support engineer told me to do that is beyond me.
He also told me to upgrade my Mac driver to 6.3.20-4, and that "should fix the issue". I asked if he would be more specific and look at the release notes, which are not public, and he came back and confirmed that this version does not fix the pen crashing issue, and that their development team is still working on it. He said they do not have a release date or estimated date when this issue will be fixed.
I was also told that unplugging the Cintiq USB and plugging it back in can fix the issue. This does not work. You need to reboot. The pen also crashes and quits functioning sometimes simply when drawing in photoshop using the pen tool, or the pencil tool.
I have two other issues with the current driver that I'm using, which is 6.3.19-10. First, certain web controls do not work. For example if you go to a web page that plays music, like certain radio stations, the play button won't work, or the volume control won't work, and some submit buttons don't work. There is no known fix for that at this time.
Lastly, I have a dual monitor setup. My monitor specs are listed on my previous post in this thread. If you zoom in on an image and it spans across both monitors, which is a very common occurrence, then a large part of the image window turns black and the Cintiq doesn't render it. This makes it almost impossible to zoom in on large images to work on details, and as I own a professional graphics and imaging business, we do this all day long. The only answer is to drag the image around so that it goes off the edge of the screen, but not onto the second monitor.
Here is a short youtube video showing this happening: https://youtu.be/c6YzQb4b5WY
I hope this information helps some of the people in this online community. I hope it helps the development engineers rewrite the drivers so we can all get back to work. Thanks.