Ubuntu 20.04 shutdown problem (no full shutdown, black screen freeze)

During shutdown using the gnome button (Power Off / Log Out in the upper right corner) my brand new Lenovo X1 Carbon won't power off properly. The power button LED switches off, the laptop appears to be powered off, but it isn't. Some keyboard key LEDs are still on (i.e. FnLock when it was switched on when I initiate shutdown).

The funny part: shutdown now on the terminal works fine.

Info: Secure boot enabled (tried with secboot switched off, no difference); i7 1165G7; Intel Iris Xe

This is the kernel log in the shutdown process:

Nov  6 08:16:47 codefactory kernel: [  265.130457] usb 3-3: reset full-speed USB device number 2 using xhci_hcd
Nov  6 08:16:51 codefactory kernel: [  268.429222] Bluetooth: RFCOMM TTY layer initialized
Nov  6 08:16:51 codefactory kernel: [  268.429226] Bluetooth: RFCOMM socket layer initialized
Nov  6 08:16:51 codefactory kernel: [  268.429229] Bluetooth: RFCOMM ver 1.11
Nov  6 08:16:51 codefactory kernel: [  268.643874] rfkill: input handler enabled
Nov  6 08:16:51 codefactory kernel: [  268.657507] evdi: [I] (card0) Opened by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657518] evdi: [I] (card0) Closed by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657524] evdi: [I] (card1) Opened by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657528] evdi: [I] (card1) Closed by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657532] evdi: [I] (card2) Opened by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657536] evdi: [I] (card2) Closed by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657540] evdi: [I] (card3) Opened by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.657544] evdi: [I] (card3) Closed by Task 2044 (Xorg.wrap) of process 2044 (Xorg.wrap)
Nov  6 08:16:51 codefactory kernel: [  268.666452] evdi: [I] (card0) Opened by Task 969 (systemd-logind) of process 969 (systemd-logind)
Nov  6 08:16:51 codefactory kernel: [  268.666735] evdi: [I] (card1) Opened by Task 969 (systemd-logind) of process 969 (systemd-logind)
Nov  6 08:16:51 codefactory kernel: [  268.667045] evdi: [I] (card2) Opened by Task 969 (systemd-logind) of process 969 (systemd-logind)
Nov  6 08:16:51 codefactory kernel: [  268.667336] evdi: [I] (card3) Opened by Task 969 (systemd-logind) of process 969 (systemd-logind)
Nov  6 08:16:52 codefactory kernel: [  269.771230] Lockdown: systemd-logind: hibernation is restricted; see man kernel_lockdown.7
Nov  6 08:16:52 codefactory kernel: [  270.049718] rfkill: input handler disabled
Nov  6 08:16:52 codefactory kernel: [  270.083972] audit: type=1400 audit(1636183012.798:44): apparmor="DENIED" operation="capable" profile="/snap/snapd/13640/usr/lib/snapd/snap-confine" pid=2512 comm="snap-confine" capability=4  capname="fsetid"
Nov  6 08:16:53 codefactory kernel: [  271.111788] evdi: [I] (card0) Closed by Task 1 (systemd) of process 1 (systemd)
Nov  6 08:16:53 codefactory kernel: [  271.111819] evdi: [I] (card2) Closed by Task 1 (systemd) of process 1 (systemd)
Nov  6 08:16:53 codefactory kernel: [  271.112211] evdi: [I] (card1) Closed by Task 1 (systemd) of process 1 (systemd)
Nov  6 08:16:53 codefactory kernel: [  271.112237] evdi: [I] (card3) Closed by Task 1 (systemd) of process 1 (systemd)
Nov  6 08:16:54 codefactory kernel: [  271.402177] audit: type=1326 audit(1636183014.113:45): auid=1000 uid=1000 gid=1000 ses=3 subj=snap.snap-store.ubuntu-software pid=2512 comm="snap-store" exe="/snap/snap-store/547/usr/bin/snap-store" sig=0 arch=c000003e syscall=314 compat=0 ip=0x7f421f150639 code=0x50000
Nov  6 08:16:58 codefactory kernel: [  275.303043] audit: type=1107 audit(1636183018.013:46): pid=938 uid=103 auid=4294967295 ses=4294967295 subj=unconfined msg='apparmor="DENIED" operation="dbus_method_call"  bus="system" path="/org/freedesktop/PolicyKit1/Authority" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.10" pid=2512 label="snap.snap-store.ubuntu-software" peer_pid=954 peer_label="unconfined"
Nov  6 08:16:58 codefactory kernel: [  275.303043]  exe="/usr/bin/dbus-daemon" sauid=103 hostname=? addr=? terminal=?'
Nov  6 08:16:58 codefactory kernel: [  275.303160] audit: type=1107 audit(1636183018.013:47): pid=938 uid=103 auid=4294967295 ses=4294967295 subj=unconfined msg='apparmor="DENIED" operation="dbus_method_call"  bus="system" path="/org/freedesktop/PolicyKit1/Authority" interface="org.freedesktop.PolicyKit1.Authority" member="CheckAuthorization" mask="send" name=":1.10" pid=2512 label="snap.snap-store.ubuntu-software" peer_pid=954 peer_label="unconfined"
Nov  6 08:16:58 codefactory kernel: [  275.303160]  exe="/usr/bin/dbus-daemon" sauid=103 hostname=? addr=? terminal=?'
Nov  6 08:16:58 codefactory kernel: [  275.312920] audit: type=1107 audit(1636183018.025:48): pid=938 uid=103 auid=4294967295 ses=4294967295 subj=unconfined msg='apparmor="DENIED" operation="dbus_method_call"  bus="system" path="/org/freedesktop/PolicyKit1/Authority" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.10" pid=2512 label="snap.snap-store.ubuntu-software" peer_pid=954 peer_label="unconfined"
Nov  6 08:16:58 codefactory kernel: [  275.312920]  exe="/usr/bin/dbus-daemon" sauid=103 hostname=? addr=? terminal=?'
Nov  6 08:16:58 codefactory kernel: [  275.313060] audit: type=1107 audit(1636183018.025:49): pid=938 uid=103 auid=4294967295 ses=4294967295 subj=unconfined msg='apparmor="DENIED" operation="dbus_method_call"  bus="system" path="/org/freedesktop/PolicyKit1/Authority" interface="org.freedesktop.PolicyKit1.Authority" member="CheckAuthorization" mask="send" name=":1.10" pid=2512 label="snap.snap-store.ubuntu-software" peer_pid=954 peer_label="unconfined"
Nov  6 08:16:58 codefactory kernel: [  275.313060]  exe="/usr/bin/dbus-daemon" sauid=103 hostname=? addr=? terminal=?'
Nov  6 08:16:58 codefactory kernel: [  275.517627] audit: type=1400 audit(1636183018.229:50): apparmor="DENIED" operation="open" profile="snap.snap-store.ubuntu-software" name="/etc/PackageKit/Vendor.conf" pid=2512 comm="snap-store" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
Nov  6 08:19:04 codefactory kernel: [  401.880855] Lockdown: systemd-logind: hibernation is restricted; see man kernel_lockdown.7
Nov  6 08:19:14 codefactory kernel: [  412.267859] rfkill: input handler enabled

I noticed the apparmor DENIED entries as well as the systemd-logind messages but didn't find any useful information that might be related to my issue.

Any hints are welcome! Thanks!