How do you handle refunds in multi-currency systems?

I keep seeing support tickets where a refund doesn’t line up with the original charge once multiple currencies are involved.

Most of the time, the math is technically right. Exchange rates move. Settlement happens later. Sometimes it’s a partial refund. But from the customer’s perspective, the numbers don’t match.

I’m interested to know how teams that own FX behavior actually handle this in practice:

Do you lock in the exchange rate at charge time and reuse it for refunds?

Do you reapply the rate at refund time and rely on explanations to bridge the gap?

Or do you cover the FX difference to keep the customer experience clean and consistent?

Was this something you anticipated early on, or did it only become a real problem once volume picked up, more refunds, more chargebacks, and more edge cases?