A .wav file attachment appears in the Notes 8.5 client just fine, no problems opening or listening to it. In iNotes, both Full and Lite it just shows up as the File Name: value in the $FILE field of the document. Something like ATT8684.
Subject: Can you give us some steps to reproduce the issue?
Subject: False Alarm
It turns out the way that some of our users are forwarding voicemails isn’t correct. It occurs in iNotes 7 as well. Sorry!