Paypal have issued a new notice today the 16/03/2020 in relation to their refunds policy. Below is what Paypal now say about refunds:
In line with industry practice and according to our updated policy, we will not charge a fee to process refunds, however fees from the original transaction will not be returned. This policy will not apply to duplicate transactions or voids. You can review the PayPal User Agreement for more information on our return policies.
This means you can refund to a client without being charged a refund fee, however you will still be charged for the original processing fee.
You can find out more information at the Paypal Website