Deactivated: WooCommerce Dynamic Pricing & Discounts = same result
Deactivated: WooCommerce Bulk Edit Product Variations = same result
Disabled coupons and your plugin, refreshed, reactivated = same result
Removed excluded items = same result
Disable Coupon pro plugin = discount shows.
Activated Coupon pro again = discount disappears again.
Once it gets a little later I will try to put store in maintenance mode and turn off plugins one by one 🙁