I had an issue where dragging a pan envelope node produced a 0% value in the drag popup value window. When I released it, the actual pan envelope value was at 40%R. I repeated this 4 times to see if it would change behavior, but it was pretty consistent. I had to add additional nodes and set the node properties to 0% and then the envelope changes and the drag value behaved.
 
Anyone have issue with any envelope processing like this?