Sounds like you have an issue with guest check out settings-
To review your Guest Check Out Settings-
Go to - https://www.paypal.com/businessprofile/settings/
Select My Selling Prefences
View Website Preferences click update
View PayPal Account Optional. Select On or Off to preference
Could be your shopping cart configurations also or an issue as you have many overseas orders. Another reason this may be happening is the credit card you are using may already be linked to a PayPal account. In this case your customer would need to log into their PayPal account to complete the sale. I hope this makes sense. But do read more...
If you require to offer a professional check out- no re-direct confusion, credit/debit cards direct on site complete with virtual terminal for telephone & mail orders & lower fees in many instances. Consider PayPal Pro (https://www.paypal.com/uk/webapps/mpp/pro).
I have a contact who works for there. My contact at PayPal can arrange an account review if you wish. He has helped saved others hundreds and in some cases thousands by advising best product to use and how to lower rates. You'd be amazed at how you can save on fees.
Let me know if you want my help simply by replying.
