Failed assertion in rdatalist.c: INSIST(list_rdata != ((void *)0))

Kevan Benson wrote to security-officer@isc.org to say:

We encountered an assertion failure in bind 9.16.3 running on an up to date CentOS 7 instance.

09-Jun-2020 13:27:19.816 cname: info: skipping nameserver 'ns1.fastclick.net' because it is a CNAME, while resolving '172.87.180.205.in-addr.arpa/PTR'
09-Jun-2020 13:27:19.816 cname: info: skipping nameserver 'ns2.fastclick.net' because it is a CNAME, while resolving '172.87.180.205.in-addr.arpa/PTR'
09-Jun-2020 13:27:20.007 trust-anchor-telemetry: info: client @0x7fdd09d71750 2602:24a:de40:7d90::#64256 (root-key-sentinel-not-ta-19036.d2a8n3.rootcanary.net): view internal-secure: root-key-sentinel-not-ta query label found
09-Jun-2020 13:27:20.018 trust-anchor-telemetry: info: client @0x7fdd116b9360 173.228.7.217#38979 (root-key-sentinel-not-ta-19036.d2a8n3.rootcanary.net): view internal-secure: root-key-sentinel-not-ta query label found
09-Jun-2020 13:27:20.581 general: critical: rdatalist.c:150: INSIST(list_rdata != ((void *)0)) failed
09-Jun-2020 13:27:20.582 general: critical: exiting (due to assertion failure)