I've had this issue across multiple installs.
On a cold boot, the taskbar (and other related ui elements) don't start. This can be fixed by restarting the gnome-shell by entering 'r' ALT+F2.
gnome-session[1166]: gnome-session-binary[1166]: GnomeDesktop-WARNING: Could not create transient scope for PID 1186: GDBus.Error:org.freedesktop.DBus.Error.UnixProcessIdUnknown: Process with ID 1186 does not exist.
gnome-session-binary[1166]: GnomeDesktop-WARNING: Could not create transient scope for PID 1186: GDBus.Error:org.freedesktop.DBus.Error.UnixProcessIdUnknown: Process with ID 1186 does not exist.
systemd[953]: gnome-launched-at-spi-dbus-bus.desktop-1182.scope: Failed to add PIDs to scope's control group: No such process
systemd[953]: gnome-launched-at-spi-dbus-bus.desktop-1182.scope: Failed with result 'resources'.
systemd[953]: Failed to start Application launched by gnome-session-binary.
(full log: Jul 20 12:31:21 zorin-desktop kernel: microcode: microcode updated early to revi - Pastebin.com)