While I am at it, here's my best guess for why some people seem to remember the grappling hook being thrown twice in ANH:

It takes a long time for Luke to get the hook/rope ready for throwing. We see him distressed and struggling with the rope, pulling it out of from his belt.

From the first shot of the hook being introduced, it takes ~23 seconds (!) until the hook is actually thrown.

One would then remember that there was SOME problem with the rope (namely the fact that it took a long time to prepare for throwing given the very bad situation Luke and Leia were in). Then someone reads the novelization or is told about it and goes: "Yea, I remember there being some problem with the hook.." and his/her mind fills the blank with the info from the novelization and what was actually seen. We see the hook being thrown so it is not a big stretch to remember it being thrown twice because most of that visual info is definitely seen.