Ignite munching is an issue which was found early in Wrath where a mage’s ignite sometimes doesn’t apply if a fireball and a pyroblast hit (and crit) at the very same time, which is a very common thing for fire mages.
There are some vague comments in the github issues page about Blizzard not wanting to fix this due to potentially causing other technical issues in the game. Well, I saw that some people are suggesting that if Blizzard can’t change the ignite scripting to be correct, then they could at least just change the projectile speed of pyroblast or fireball. This would add a natural delay between every instance of fireball + instant pyro and thus eliminate most instances of ignite munching. Seems pretty reasonable to me.