Not long ago I lost against a Hiogi combo deck of which animation lasted so long that when was my turn the time bar reached the end in a few seconds letting me no time to answer in any possible way. I thought was a bug so I made a report and Duelyst Support Team said this:
“The apparent bug you encountered is actually the normal gameplay; it can happen that a player uses a long succession of spells and/or summons a lot of minions. However, the game cannot hurry the cards’ animations, so it might seem as they surpassed their allotted time, but that’s just a visual hiccup, as they still have to cast spells and summon minions in the same time frame.”
On one hand it’s a very rare happening so I don’t bother too much, but I still think it’s not right.