Comment 8 for bug 2009858

Hi, this issue also effects domain join.

tested with focal:
Ubuntu 20.04.6 LTS

net ads join member -U <user> osName=Ubuntu osVer=`lsb_release -rs` -S <DC>.<DOMAIN>
Password for [<DOMAIN>\<USER>]:
Failed to join domain: failed to find DC for domain member - A domain controller for this domain was not found.

When I downgrade the packages:
upgrade samba-common:all 2:4.15.13+dfsg-0ubuntu0.20.04.1 2:4.13.17~dfsg-0ubuntu1.20.04.5
upgrade samba-common-bin:amd64 2:4.15.13+dfsg-0ubuntu0.20.04.1 2:4.13.17~dfsg-0ubuntu1.20.04.5
upgrade libwbclient0:amd64 2:4.15.13+dfsg-0ubuntu0.20.04.1 2:4.13.17~dfsg-0ubuntu1.20.04.5
upgrade libldb2:amd64 2:2.4.4-0ubuntu0.20.04.1 2:2.2.3-0ubuntu0.20.04.3

The join is running again:
net ads join member -U <user> osName=Ubuntu osVer=`lsb_release -rs` -S <DC>.<DOMAIN>
Password for [<DOMAIN>\<USER>]:
Joined '<Server>' to dns domain '<domain>'

Edit:
Deployed a new VM (before patch) and pinned samba-* (apt-mark hold samba-*). Updated the system (with pinned package) and domain join is OK.

apt-mark showhold:
samba-common
samba-common-bin
samba-dev
samba-dsdb-modules
samba-libs
samba-testsuite
samba-vfs-modules

In my case:
This packages gets hold back, if I try to apt upgrade after I pinned samba-*:
fwupd libfwupd2 libfwupdplugin5 libipa-hbac0 libldb2 libsmbclient libsss-idmap0 libwbclient0 linux-generic-hwe-20.04 linux-headers-generic-hwe-20.04 linux-image-generic-hwe-20.04 python3-ldb python3-samba python3-sss samba-common samba-common-bin samba-dsdb-modules samba-libs sssd sssd-ad sssd-ad-common sssd-common sssd-ipa sssd-krb5 sssd-krb5-common sssd-ldap sssd-proxy