Expert Tepee sliding door- sticks open

[hedgerowpete]

When ever I open the sliding doors, I have no issues whatsoever. They go all the way back to the bump stops. Nice and smooth, no issues.

But trying to close them is a nightmare. The bottom roller set seams to be stuck or locked into place. I am either going to rip the handle out of the door one day or i have to push from the rear open edge to get the door started.
What makes the bottom roller set lock into place, and what do I do to improve it?

Many thanks