After days of frustration, I finally figured out that the doubling of note and controller events isn't the fault of the X1, but a miscommunication between X1 and Cakewalk. Basically, I am using one of pedals on the F-13 footswitch as a sustain pedal. This sends a system exclusive message F0 26 79 00 7F F7 to Cakewalk. The X1 wants to communicate that the one of the footswitches is being used as a sustain pedal, but Cakewalk interprets it as double all events being recorded. When I temporarily cancel sys ex recording, the recording is perfect and I still get sustain out of the footswitch on playback. I'm going to buy a regular expression pedal that doesn't send a sys ex message to Cakewalk. I haven't had any problems with any other sys ex messages that the X1 sends to Cakewalk. I guess this is just a glitch.