When you have 1 stack left of Gateway and click Gateway, it doesn't consume the buff
Not sure if the gif explains it all. Pretty much I used gateway 3 times, but I still had the buff after, even though I had 0 stacks.
It should just completely remove the buff when you have no stacks.
Also, when you summon Gateway, the first stack you get, doesn't work, it displays the buff, but it has 0 charges.
Also, first stack should be given after 5 seconds (only the first, then after it should be every 10 sec for the other ones)