I came here to report this very problem, but "reportbug" suggested I try the dbus from experimental(!), so I did, and the problem (in my very limited experimenting) seems to have gone away...
$ sudo systemctl status dbus ● dbus.service - D-Bus System Message Bus Loaded: loaded (/lib/systemd/system/dbus.service; static) Active: active (running) since Sat 2021-05-15 10:41:05 EDT; 5s ago TriggeredBy: ● dbus.socket Docs: man:dbus-daemon(1) Main PID: 1599 (dbus-daemon) Tasks: 1 (limit: 4810) Memory: 768.0K CPU: 83ms CGroup: /system.slice/dbus.service └─1599 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only May 15 10:41:05 alphatest systemd[1]: Starting D-Bus System Message Bus... May 15 10:41:05 alphatest systemd[1]: Started D-Bus System Message Bus. $ uname -a Linux alphatest 5.10.0-6-alpha-generic #1 Debian 5.10.28-1 (2021-04-09) alpha GNU/Linux $ dpkg -l | grep dbus ii dbus 1.13.18-2 alpha simple interprocess messaging system (system message bus) [...] - Rich