From today's update:

Abilities

• Fixed an issue where Hunter class ability cooldown times would increase if the player's Mobility stat was over 100.
  
• Players may now increase their Mobility to whatever value over 100 that they desire without detriment to their cooldown timers, even if it provides no real benefit.
  • Seriously, go ahead.
    
  • Max that stat out.
    
  • We dare you.
    
  • Show us how high you can get your Mobility.