This happened to me last week and a GM said to post this as a bug. Then it happened to me again this week, so I thought I’d better do it 
I’m trying to do the Ley Race quest and when I get on a mana saber instead of riding it I get thrown off and stunned for several seconds. It also seems to make any movement impossible for a while even after the stun wears off. I tried hearthing out and coming back, and tried restarting the game, but no joy. The GM said he logged in as me (Gentiana - Dragonblight) and saw the problem and would forward it to you folks, and that I should post it as well.
I can do it fine on other toons, it’s just Gentiana that has the problem. And she has the problem for both the Aszuna and Suramar versions of the quest; last week she was able to do the Stormheim version.
Thanks!
EDIT: I did the Ley Race quests on 11 other toons, and only one of them did not work, in just the same way. That was Pirixia-Dragonblight.
I just ran into this on my Alliance Monk. I click on the Mana Saber, it shows the animation of hopping on the saber, but then I get stunned for 3 seconds & can’t move. The saber I “hopped” onto disappears while I’m stunned & I have to log off/on to move again.
It does give credit for “Ride Mana Saber” & I can see the yellow dots on the mini-map for the ley lines, but obviously can’t satisfy the remaining requirement since I can’t move.
I never had this issue on my other toons. This happened while the Kirin Tor Emissary was up & while attempting the Ley Race in both Azsuna & Stormheim.
Same thing happened to me on 1 of 7 toons. As suggested in another post, I removed mt HoA necklace and it worked just fine.
3 Likes
Just wanted to add that this is still happening. Only one toon affected: Ylvaa - Laughing Skull.
It’s happening in Highmountain, Azsuna, and Suramar versions of the world quest
1 Like
Removing HoA necklace worked for me Nov 2020