I'm not so sure you could consider that as sharp. Looking at the side view I see a fairly nice radius thanks to the folding of the corroplast. What I DO see is perhaps a shallower than normal curve on the leading edge...... and gobs of wing area. Perhaps it's flying well thanks to the area? And the strongly cambered section with the "flap" deflection in the rear. Strangely enough what you have for a shape there isn't far off some sailplane airfoils and follows a number of the rules of thumb for free flight airfoils other than thickness.

It would be interesting to run this shape through Xfoil.

PS: considering John's rotor theory I can see how such a little rotor bubble could be filling in the flat'ish upper entry just behind the leading edge.

John, could such a bubble act as a turbulator to encourage high AoA flight without stall separation?