issue with bound skill

I am not sure what could be causing this. Everytime my ranger leaves an instance, a port back to town, 2nd phase of a boss fight, my right click lightning arrow no longer works. It still shows the image, but the skill does not work unless I reassign it. It is making my level 95 ranger unplayable and need to get to the bottom of the issue. Please help.

This is not occurring on my other 2 characters so it is something specific to my ranger.

Only thing I can think of is if you weapon swap? If so go to lightning arrow skill and disable it for weapon set 2.