My TestFlight app isn't receiving APNs push notifications, however my development app receives them correctly. This seems to suggest that it's a problem with my Apple certs/profile/etc. There are numerous SO questions on this topic, but none of them helped me.
I'm using Phonegap Build to build the app -- not Xcode.
I tried regenerating all the certs/profiles/.p12 files, all of which are set up for distribution rather than development.
In my config.xml, I've set the "aps-environment" entitlement to "production". I've also confirmed that my provisioning profile contains the aps-environment "production" entitlement, as described here.
<config-file target="*.entitlements" parent="aps-environment">
<string>production</string>
</config-file>
I regenerated the cert/profile/.p12 about 3 more times and it finally started working. Not a very satisfying answer, but there you go.