Toyota Tri fold Tonneau leaking at left rear

I recently had a Toyota OEM Tri fold Tonneau installed by Toyota service and it leaks at the left rear.
I park on a slight grade and it looks as if water is pooling in the top channel and leaking out onto the left rear of the bed.
I was wondering it this is common or should I take it back.
It is not a big deal but I was hoping these covers were somewhat water tight. The rest of the bed seems quite dry.

 

I guess nobody has a leaky tonneau!

 

mine leaks too.. I got some Rubber seal from Home depot, that you would use on a door jam, it sorta helps.. A LOT less water after putting in. I will most likely get some thicker rubber and try again and get a tighter seal. If you find a better solution let me know