>When you <climb fall with my lead rope>, it tells you that having the lead rope in your hand makes the climb more difficult.

You need a heavy rope to aid climbing, not a lead rope.

When you have an item in either hand that isn't a heavy rope (or climbing rope of some sort) it increases the difficulty of the climb. Holding a lead rope is making the climb more difficult. That's what the messaging reflects. What bug are you reporting?