So I’m playing with Green Goblin and his Glider countdown tile got destroyed before I could fortify it with his Yellow power.
Now it NEVER comes back…
So, on a wave node, that’s kind of frustrating.
Is that the intention? 
…yeah, that’s the intention.
The risk of losing the skill if you don’t defend the countdown tile helps to justify the skill’s massive damage.
Seriously, it’s a really big hit for the cost. All things considered, it’s an interesting game mechanic, IMO.
Try to clear as many matchable black tiles off the board before using it. It’s a nice big hit, but if you have a bunch of black on the board, with the AI luck, it could be a one hit wonder. As long as the person you are targeting doesn’t have enough AP to destroy you with some huge attack, you can wait a turn or two to use it so you can clean up the black tiles on the board to limit its spawning options.
It is also part of why he has the fortify mechanic.
I thought this was a bug too. I try to only use this power, and it’s a good 'en, when there are no other countdown tiles for GG to fortify so the Glider tile only needs to survive one enemy round.