Spells while hidden

[Tarven]

Apparently, casting a spell while hidden, even on self, breaks hide. Is that intentional? Only when using verbal components? Seems like it could/should do the 'someone utters the words' part, perhaps, if silent spell isn't being used, the way it happens when someone speaks or emotes, but shouldn't it not break hide until the effect actually lands?

[Nylo]

It shouldn't if there's no verbal component, but otherwise you're making noise the whole time. "You begin to chant/sing/pray"