There is also another bug with this ability but I reported it already in game.
"... and the blue fire of Helluin flickered in the mists above the borders of the world, in that hour the Children of the Earth awoke, the Firstborn of Ilúvatar."
Welcome to the game. Blazing shield dismounts when it ends, I've been dealing with it for ages now I'd love it if they fixed the dismount issues, but just a warning it's been around for many other abilities for a long time.
Stands-Strong-As-Snow ~ Argonian Templar DC NA V14 Ytheri ~ Argonian Nightblade EP Thornblade NA V14 Heals-All-Colours ~ Argonian Templar EP Thornblade NA V14 Stands-In-Still-Waters~ Argonian Sorcerer EP Thornblade NA V2