I found https://snapcraft.io/docs/snap-try and was able to use this procedure to get a tree based on the latest 3.4/edge (maas_33732.snap) that I could hack up and run.

I added the following tracing:

--- ./lib/python3.10/site-packages/provisioningserver/utils/network.py.orig     2024-02-26 18:12:45.469928677 +0000
+++ ./lib/python3.10/site-packages/provisioningserver/utils/network.py  2024-02-26 18:23:53.355421849 +0000
@@ -768,6 +768,9 @@ def safe_getaddrinfo(hostname, port, fam
     def _v6_lookup():
         resolver = getResolver()
         answers = yield resolver.lookupIPV6Address(hostname)
+        import logging
+        for ans in answers[0]:
+            logging.error('_v6_lookup ans: %r', ans)
         return [
             (AF_INET6, sock_type, proto, "", (ans.address, port, 0, 0))
             for ans in answers[0]
@@ -827,6 +830,17 @@ def resolve_hostname(hostname, ip_versio
     # The contents of sockaddr differ for IPv6 and IPv4, but the
     # first element is always the address, and that's all we care
     # about.
+    import logging
+    for address_info_rec in address_info:
+        logging.error('one item in address_info: %r', address_info_rec)
+        for one_entry in address_info_rec:
+            logging.error('     - %r', one_entry)
+        try:
+            family, socktype, proto, canonname, sockaddr = address_info_rec
+            logging.error('%r, %r, %r, %r, %r', family, socktype, proto, canonname, sockaddr)
+        except Exception as e:
+            logging.error(e)
+
     return {
         IPAddress(sockaddr[0])
         for family, socktype, proto, canonname, sockaddr in address_info

The result:

2024-02-26 18:28:42 root: [error] one item in address_info: (<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('172.21.66.4', 0))
2024-02-26 18:28:42 root: [error]      - <AddressFamily.AF_INET: 2>
2024-02-26 18:28:42 root: [error]      - <SocketKind.SOCK_STREAM: 1>
2024-02-26 18:28:42 root: [error]      - 6
2024-02-26 18:28:42 root: [error]      - ''
2024-02-26 18:28:42 root: [error]      - ('172.21.66.4', 0)
2024-02-26 18:28:42 root: [error] <AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('172.21.66.4', 0)
2024-02-26 18:28:42 root: [error] one item in address_info: <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0>
2024-02-26 18:28:42 root: [error] _v6_lookup ans: <RR name=ci-maas.eng.exagrid.com type=AAAA class=IN ttl=3468s auth=False>
2024-02-26 18:28:42 root: [error]      - <Deferred at 0x7fddd7bf01c0 current result: <twisted.python.failure.Failure builtins.AttributeError: 'RRHeader' object has no attribute 'address'>>

Not sure why the twisted DNS resolver is getting that result. The name in question resolves fine:

root@smaasc1008:~/squashfs-root# host ci-maas.eng.exagrid.com
ci-maas.eng.exagrid.com has address 172.21.66.4
ci-maas.eng.exagrid.com has IPv6 address 2602:fbab:e0:1066::4