Yes, only use 1-2x multiplier and it will be normal
You can use higher multiple when the battle time more than 1 minutes
I think they use our battle time to make it happen to us, i tried use 7x multiplier when the battle time over than 1 minutes
But idk when our CP is lower than the recommend CP, cause i already done hard level 6 before they update the system, i need leveling up than try the hard level again