So if you don't know M2's tele has some weird properties that go like this: if used in the ground, M2 can double jump and act, if used in the air while you have a double jump, you can act but it will exhaust the double jump, if used in the air with the double jump already, you will go into special fall(helpless). Floating is also very weird. It uses your double jump when you do it, but you can only use it once per air time and you have to land to the stage to refresh it(meaning ledge grab won't refresh it), and you also can't do it after an upB. It does take up your double jump so it float then upB, you will go into special fall. Hope fully this clears that up, I know it's complicated.
Because you technically can't double jump after jump->UpB, my guess is you are accidentally ledge canceling the teleport. You still can teleport to the ledge, M2 can't grab ledge backwards(I am pretty sure), so you have jump then shortly after teleport in the direction, but while in the midst of teleporting move the ctrl stick towards the stage so M2 will be facing the stage when finishes the teleport so he can grab ledge.
tl:dr : you can't double jump after jump-> upB, and you can never float after a teleport, tele to ledge: short hop to upB, but snap ctrl stick back towards the stage.