Soooo this is still an issue I see this was irritating me so much I used Google to see if there was a solution I'm sooooo glad more than 3 years later that this is still an issue. I am constantly being bombarded when with this pop up. I have my glider, and my mount, and still this is an issue. It is because I have unspent mastery points it wants me to spend in Central Tyria and it doesn't matter if I don't want to spend it on Fractals ( I doubt I will ever play fractals) I want to spend it on the Legendary Crafting and I need two additional points. Like seriously it is beginning to irritate the hell out of me there should simply be an option to disable in game. I'll submit a ticket to see if there is a solution.