I mean, Trey isn't wording it very clearly, but she's by no means wrong. Walking off a ledge does not reset your double jump counter. If you jump, double jump, land, then walk sideways off a ledge and begin falling without having jumped again since your last double jump, you won't be able to do another double jump while falling. This is how the game has always worked.

Similarly, it's true that even when you are allowed to make a double jump, there are restrictions on how long it has to have been since you last pressed jump, so if you wait long enough, you have to double-tap the key in order for the jump to work.