Ah right, I know why this is happening.
Formerly all bosses were forced to use the same typical Eggmobile thinker, which was mostly done by "A_Boss1Chase" an action formerly not usable for SOCs either.
NOW A_Boss1Chase has been seperated out from the custom boss, and has also been made usable for SOCs if you wanted. A_Boss1Chase does all the usual Eggmobile flight as well as deciding which attacks to use and stuff.