That is -the- dumbest thing I've read in a long time.
The cast is important because there's about a 90% chance that cast is required.
And, before 2.3, there was no risk at all of it causing a problem because even if the spell landed with the bulb essentially already dead, I'd still get my Umbral Ice III. It's only a problem at all now because SE fucked it up when they were making changes to get rid of infinite flare.