The dash bug is when a character in Battlefields uses a Dash skill on an enemy player the user SOMETIMES dashes foward to the character stuns, and dashes back to the original location (happens about 20% of the time) or flys across the map (happens about 5% of the time)
Skills that have the dash bug:
Commander: Rush
Warrior: Charge
Berserker: Burning Dash
Assassin: Brutal Scud
It is more likely to happen when the user is far away like 25~30m
Good Luck!