Stacking durations on Attributes sets them permanently

5.3.5 Premium || MM Devbuild 5.4.0 d8c02879 || Spigot 100 and more. Just use this: "/mm test mechanic - attribute{attribute=GENERIC_MOVEMENT_SPEED;a=1;duration=20} @self" and spam it until you stack it. It causes a bug where you are stuck in warp speed. Despite having a duration.