Check out the patch notes for the v17 Precursor Update here:

[Combat] Teleport and Jumping Bug

MapleStory 2 Rep: 1,910
Posts: 78
in Bug Reporting
Server: NA East
Class: Wizard

- Holding ← + ↑ + Jump does not work
- Holding ← + ↑ + Teleport does not work
- Housing Furnishing Mode, cannot place furnishings continuously in the ← + ↑ direction.

Conditions of Situation:
- I changed jump key to Spacebar
- Any other directional key combination with Jump/Teleport does work
- Furnishings can be placed continuously in any other directional key combination.
- On Thief, any directional key + Mind Stealer combination works.
- On Rune Blade, any directional key + Blink combination works.