You have a cascade of postfixes and aliases your mails are traversing through and are losing the original recipient address?
Simply add a header line with first servers postfix.
Tune your main.cf and add something like the ‘detect_recipients‘ line here:
smtpd_recipient_restrictions = check_recipient_access regexp:/etc/postfix/specials/denied_recipients, check_recipient_access regexp:/etc/postfix/specials/allowed_recipients, check_recipient_access regexp:/etc/postfix/specials/detect_recipients, check_recipient_access regexp:/etc/postfix/specials permit_mynetworks, reject_unauth_destination
Your detect_recipients file:
/^(.+)$/ PREPEND X-Original-Rcpt: $1
This will add a header line.