Sign in with Apple private relay emails blocked

My partner used Sign in with Apple to create an account with Vinted (an eBay like company) this generated a new email address <example>@privaterelay.appleid.com. Vinted sent a parcel via a courier (Yodel) giving the courier this email address. It seems that privaterelay email addresses are blocked from arriving if they originate from outside the domain used when creating the account (eg. Vinted.com). Is there any way of rectifying this?

NB email addresses created using the hide my email process during a sign up outside the Sign in with Apple flow are unaffected by this issue.

Perhaps blocking privaterelay emails from external domains is intended behaviour, but it is hugely problematic when a company needs to legitimately share this email with a third party such as a courier…