SPA-3000 not answering calls when "PSTN CID for VoIP CI

PSTN CID For VoIP CID: No
SPA3000 answers calls coming in on my PSTN line, and routes them correctly to Asterisk (but, obviously, with no CID (call ID)).

PSTN CID For VoIP CID: Yes
SPA3000 just lets the phone ring and ring and ring. Asterisk shows nothing, even with verbosity set to 10.

For testing purposes, I have “PSTN Answer Delay:” set to 15 seconds, to ensure that the SPA3000 has time to receive the CID, but when I plug my analog phone directly to PSTN, the CID pops up on the phone after roughly 2.5 seconds.

I’m running software version 3.1.20(GW) and I have hardware version 2.0.1(25e9).

Can anyone help me figure out why I can’t get my SPA3000 to answer an incoming call when “PSTN CID For VoIP CID” is enabled?