Hey hey 
It’s as Potemkinz and Kezef have said this isn’t a bug. If one Troop with Quick Trait has the status effect of being Frozen, but another Troop in that team also has the Quick Trait the extra turn will be granted as each Troop Ability and Trait is independent from one another.
I hope that helps clear up any confusion.
OminousGMan - Team Support Human