While in an online server flying over water I noticed that the Huron's shadow only rendered the shadows of the rotors and not the rest of the hull.
After a few minutes of testing in the editor I found out that the hummingbird does cast it's shadow properly on the water and the Ghosthawk doesn't cast a shadow on the water at all.
-open the editor
-spawn a playable character
-spawn a few helicopters
-fly towards the coast
-see what happens with your shadow while flying above the ocean.
I've tried this on the Altis map only and only with the ghosthawk, humingbird and Huron so far, will test all the other helos and also the other maps and will report in with more info about the other vehicles
I've tested most other helicopters at the moment and almost all helicopter shadows didn't draw properly
MH9/AH9 rendered correctly
MH900 didn't seem to cast a main rotor shadow
CH67(black/normal) rendered both rotors but no hull shadow
AH99 only seemed to cast a shadow of the anti-torque/tail rotor
all other choppers didn't cast a shadow on the water at all.
Added 2 zip files (chopperShadowTest1-2 & chopperShadowTest2-2) containing screenshots from almost all helicopters and a txt file explaining the things because not everything is visible on stills