May want to move this to Shipping forum https://community.shopify.com/c/Payments-Shipping-Fulfillment/bd-p/payments-shipping-fulfilment
Is the result the same if the customer used western characters to type the address, or you use germin(?cryllic?) characters? e.g. ß
I have some experience with troubleshooting this type of stuff. If you like, I can send you a Partner Collab invite and take a look for you. I will need the customers name or email to look up the abandoned cart, so i can compare them and see whats happening.