Grappling hook is inconsistent

[Ethan_sedai]

The grappling hook is really inconsistent as to whether or not it works. Sometimes it'll work perfectly fine, other times, I'll press the button while the red line is present both before and after I press the button, and it just doesn't grab, even though the red line is there.

Is there some sort of hidden condition that needs to be met for the grapple to work, besides being in the air and the red line being there?