Wrong total price displayed, when operating with multiple currencies

[Fanfe]

Hey!

Been using PS for more than a year and ONE of my customers encountered a weird bug (this has never happened before, nor I was able to reproduce it when choosing the exact options he chose)..

My default shop currency is PLN, he paid in USD.
Looks like some module did not convert currencies properly, he paid the right amount after all, but was pretty scared, when the shop displayed total amount that was 4x bigger - price in PLN, not converted to USD, but with $ sign.
He paid with PayPal (official module from paypal).

This is what I see in order details from backoffice:

 

This is what customer saw in order confirmation page:

 

Customer bought this item:

 

This is how prices are configured for the item:

Also it was the last one in stock, could this be the reason? (again, I reproduced it and got normal price displayed in the end)

Overall the right amount in USD was paid, nothing more, nothing less, so that's good. Nevertheless I don't want to scare any of my dear customers if that happens again..

I'm on PS 8.2.0.
Can someone please point me where to look for (which module / script can be responsible)?
Or at least where I should put some scripts that could log what is happening with the price?

Edited Tuesday at 02:51 PM by Fanfe (see edit history)