Figured it out. Paging module is detecting Polycom in [macro-autoanswer] and switching the Alert Info header to “info=Auto Answer”, which is (obviously) not the default “Ring Answer”. Not sure why they did that, as every Polycom tutorial on earth uses “Ring Answer”. In any event, all you have to do to fix is switch the line:
voIpProt.SIP.alertInfo.1.value="Ring Answer"
to:
voIpProt.SIP.alertInfo.1.value="info=Auto Answer"
in your sip.cfg file (in endpoint manager - if you are still using it - or in the ftp/tftp root for your Polycom setup files), and paging will magically start to work.