Teleporting to the air counts as being OnGround?

I'm trying to make a feature where if you press Shift (sneakTime), you will teleport 1 block below until you reach the ground... But apparently, teleporting makes you count as being on ground for what might be a split, which forces me to HOLD to do the feature instead of PRESSING.

Not only that, but I also made it so it plays a sound when I do that.