Cashback for WooCommerce

There is a bug with the amount of cashback that is rewarded when someone purchase using the cashback (version 4.6.0)

It is deduction the cashback again after the total to calculate.

For example, I reward 20% cashback

The subtotal is $1.000
The client use $100 cashback
The total goes to $900

He should receive $900 * 20% = $180 of cashback

Instead its doing $900 – $100 again, and then calculating the cashback with $800 * 20% = $160

Need to fix this