[Exim] multiple PTR and HELO check

Sorry if this has been discussed, I have the impression it might, but
it appears that exim does not deal well with multiple PTR records.
I have received an email (spam) with:

Received: from mail.univie.ac.at ([131.130.1.27] helo=mailbox.univie.ac.at)

but

;; ANSWER SECTION:
27.1.130.131.in-addr.arpa. 60402 IN     PTR     mail.univie.ac.at.
27.1.130.131.in-addr.arpa. 60402 IN     PTR     mailbox.univie.ac.at.

so it looks like exim stopped at the first PTR.

Giuliano