I'm with Longers and toppleover... got same kite exactly - no problems ever.
As previously mentioned the kite has awesome depower so I am surprised too by your problem. Better check what it is you call 'well inflated'... When I started I also thought my kites were well inflated and later I found out they were soft as bananas

. One more PSI can just be the Viagra the kite needs.
Ask a more experienced kiter around you and learn the sound the kites make when you flick the bladder at inflation, or bending the leading edge when you think it is done. It soon will become second nature.
Note: if you hear a boom sound.. it was too much[}:)]. Life's about balance ..