Discount not 100% working with the Woocommerce Currency plugin

We have a discount rule set Buy 2 items and get extra 20% off. Customer orders which made in Hong Kong are all doing fine. But orders which made in Malaysia and Canada have granted Extra 20% off x 2 times (meaning granted extra 36% off)

We don’t have other overseas order except the mentioned 2, we are not sure what is going on? Urgently require help!

Here’s the DISCOUNT plugin developer replies after all the discount rules are confirmed to be working fine:

Do you have any other third party plugin to change product price based on the customer’s IP address?

Our plugin will not change product price based on IP’s. You can deactivate both of plugins and have a check on the same.
We recommend you to have a check with respective plugin dev team regarding the same.
Kindly have a check and let us know.

I am attaching the whole conversation records (1 is the olderest, 17 is the lastest):

I don’t think the photo details are helpful, you can check it from the backend.

Please let me know if you need further info. There are totally 17 screenshots but I am only able to send 4 here.