I'm not sure what is bugged here but there seems to be an actual number of seconds to do it.
I tried for more than an hour but could not Winter, Autumn, Summer (Spring isn't a problem) to activate together.
I dropped the resolution and then it worked first time.
If it is true that you are limited in completing this quest because your GPU will not finish the previous animation in time then that is sad (or at least something to be aware of)
It could be a coincidence though but I doubt it. I was pretty snappy at the hail, electric bolt, laser thing after 400 goes - you just spam the hot key for the next spell until the animation for the last one finishes.
