sorry for the delayed response
you may have figured this out already but i'll throw in my 2 cents...

2 things...
- when you activate the handle to drive the unit the electric brake you will hear releasing, this will sound like a click or popping sound. You will also hear this when you stop driving and release the handle back to the rest position.
- a known issue with some of the control handles on these units is the return spring inside the control handle head. The standoff for the spring tension arm may be shallow allowing the spring to slip or pop out of position.
remove the handle cover and check the return spring.