Looks like something that can easily be solved by tweaking the curve. I also don't think you'll be doing such sharp turns often, and at that angle and speed you may as well get off.
On the contrary, it's a fundamental flaw in the design. The second to last photo shows the trailer directly over the pedal which will inevitably either push the rider's leg off or limit the turn radius.
It's pictured at the furthest back position for the pedals though which means your leg will mostly go forward of the pedals and not much back. I would trust people having actually ridden this to not have their legs slammed into the trailer vs how it looks on one render or photo.
