Anything but compliance is flaky. Anything but a flat out yes is a no or flaky. When you dont get a straight answer. When they cancel. When they make excuses. When they dont comply.What would constitute flaking behaviour? At what point to you say Im outta here. I have known some people to call out their behaviour and if they don't change it, they are gone.
When they jack you around looking for attention all the time and suddenly vanish when you try to make plans.
Calling out their behaviour is a waste of time. You absence will speak louder than any words you could use. If it doesn't then your presense meant nothing to them in the first place.