Jerk

Not sure if this is your problem, but a bug in the firmware was identified that causes “jittering / shaking” during curves a few weeks ago. Less than a day ago, V1 dropped new firmware that contains the fix. I believe the fix was just a setting change, so if you are not running V1 firmware, you can do a diff on configuration.h to see the fix.

Edit: I just took a look at the configuration.h file for the lastest V1 release and compared it to what I am running (which has the jittering behavior). CLASSIC_JERK is turned off in the latest release which I believe is directly related to this bug.