My boosted breed on small account is no longer free. While trying to breed using Forest and Fire, I used boosted breed and got a popup saying "you do not have enough gold to make this purchase". Restarted and tried again and gold cost for boosted breed is 12 gold again. I hope it didn't take gold from my main account, I used it while it said 200 coin but obviously this didn't make a difference with the glitch.
I would check, but I have an aether in my breeding den and it isn't set to go into the nest until tomorrow afternoon.