regression-update: Unexpected Results 'iw reg set US'

I'm trying to diagnose why I'm unable to connect to a 5GHz WiFi access point from my Ubuntu 20.10 Raspberry Pi 4B 8GB. I wondered if it might be a problem with the crda. The default /etc/default/crda did not specify a country code. I edited the file to change "REGDOMAIN=" to be "REGDOMAIN=US" and rebooted.

After I run "iw reg set US", I get unexpected results for "iw reg get", that don't match the output from my Ubuntu 16.04 laptop.

$ cat /etc/default/crda
# Set REGDOMAIN to a ISO/IEC 3166-1 alpha2 country code so that iw(8) may set
# the initial regulatory domain setting for IEEE 802.11 devices which operate
# on this system.
#
# Governments assert the right to regulate usage of radio spectrum within
# their respective territories so make sure you select a ISO/IEC 3166-1 alpha2
# country code suitable for your location or you may infringe on local
# legislature. See `/usr/share/zoneinfo/zone.tab' for a table of timezone
# descriptions containing ISO/IEC 3166-1 alpha2 country codes.

REGDOMAIN=US

$ iw reg get
global
country AL: DFS-ETSI
 (2400 - 2483 @ 40), (N/A, 20), (N/A)
 (5150 - 5250 @ 80), (N/A, 23), (N/A), NO-OUTDOOR, AUTO-BW
 (5250 - 5350 @ 80), (N/A, 20), (0 ms), NO-OUTDOOR, DFS, AUTO-BW
 (5470 - 5725 @ 160), (N/A, 26), (0 ms), DFS
 (5725 - 5875 @ 80), (N/A, 13), (N/A)

$ sudo iw reg set US

$ iw reg get
global
country 98: DFS-UNSET
 (2400 - 2472 @ 40), (N/A, 20), (N/A)
 (5150 - 5250 @ 100), (N/A, 23), (N/A), NO-OUTDOOR, AUTO-BW
 (5250 - 5350 @ 100), (N/A, 20), (0 ms), NO-OUTDOOR, DFS, AUTO-BW
 (5470 - 5725 @ 160), (N/A, 23), (0 ms), DFS
 (5725 - 5730 @ 5), (N/A, 13), (0 ms), DFS
 (5730 - 5850 @ 80), (N/A, 13), (N/A)

On my Ubuntu 16.04 laptop, 'iw reg get' returns 'country US: DFS-FCC' and a different list of frequency bands.

$ sudo apt-cache policy wireless-regdb

wireless-regdb:
  Installed: 2020.11.20-0ubuntu1~16.04.2
  Candidate: 2020.11.20-0ubuntu1~16.04.2
  Version table:
 *** 2020.11.20-0ubuntu1~16.04.2 500
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages
        500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu xenial-security/main i386 Packages
        100 /var/lib/dpkg/status
     2015.07.20-1ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu xenial/main i386 Packages

$ iw reg get
country US: DFS-FCC
 (2400 - 2472 @ 40), (N/A, 30), (N/A)
 (5150 - 5250 @ 80), (N/A, 23), (N/A)
 (5250 - 5350 @ 80), (N/A, 23), (0 ms), DFS
 (5470 - 5730 @ 160), (N/A, 23), (0 ms), DFS
 (5730 - 5850 @ 80), (N/A, 30), (N/A)
 (57240 - 71000 @ 2160), (N/A, 40), (N/A)

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: wireless-regdb 2020.11.20-0ubuntu1~20.10.1
ProcVersionSignature: Ubuntu 5.8.0-1013.16-raspi 5.8.18
Uname: Linux 5.8.0-1013-raspi aarch64
ApportVersion: 2.20.11-0ubuntu50.5
Architecture: arm64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sat Feb 6 00:15:23 2021
Dependencies:

ImageMediaBuild: 20201022
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: wireless-regdb
UpgradeStatus: No upgrade log present (probably fresh install)