Unfortunately, staff dissmised that tiocket so I am unable to comment there (which is weired that even comments are not allowed, but ok).
I linked there a discussion from blizzard offical which says somethig different. Here it is the link (again)
https://us.forums.blizzard.com/en/wo...knives/1362771
There is a link to the video
https://www.youtube.com/watch?v=pBSARrcD-L0
Which is used there as a proof that Fan of Knives clearly returns energy from both weapon since it refresh more than 2*number of targets energy (about 3:15). So we have staff member with old logs back in time which says one claim and we have discussion on blizzard forum with link to the video which claims exactly oposite. Maybe it was a bug in older patch and was fixed during wotlk lately?