Sidebar Cart Subtotal shows double discount

I have created a bulk discount whereas, if customer buy 50 or more items, there will be additional 10% discount.

However, the subtotal seems to show double discount. See below example:

Item 1 price: 23.50
Quantity: 50
Subtotal 952
Actual cart subtotal: 1057.50 (-10% discount – correct)

After adding 50 items in the cart the price change from 23.50 to 21.15 (which is correct).
Multiplied by 50 quantity, the subtotal should be 1057.50 (this is the amount showing in the cart page) but the sidebar cart is showing 952.

Can help me resolve this issue?
Thank you so much for assistance.