Dual Bladers receiving 2 MW 10's

Describe the problem. Be as specific as possible!:
After scrolling MW 10, a quest pops up saying that I lost MW 10 skillbook lol.

 Images of problem

Quest was intended to those who accidentally dropped it.

Quest was intended to those who accidentally dropped it.

Only instead, it seems to work on Dual Bladers after they actually used it.

I don't really see the problem, you can't use it or anything. Might as well drop it.