I am using Magento 2.3.2 Enterprise Edition. Problem might be there in open source as well.
Please follow the steps to produce the issue :
- Apply a custom price using event "checkout_cart_product_add_after".
- Select "Apply Tax On" option as "Custom price if available" in Tax settings in admin configuration.
- Please add 2 currency rates as desired.
- Now add product to cart and observe the price in mini-cart or cart page.
- Symbol is getting changed but the currency is not getting converted.
e.g if IQD5,956.75 is the custom price of the product which is equivalent to 5$, will not be carried out to cart page. In cart page, you will find IQD5 as the item price when added to cart.
Let me know if more information needed on this.