gnome-shell at 5-6% of CPU all the time

My Ubuntu since recently started to consume 5-6% of CPU while idle (I wouldn't have noticed if it didn't cause cooler to spin :/ ). Looking into the System Monitor -- it's gnome-shell. I've tried disabling all extensions (and of course rebooting) but it didn't help. So I've tried journalctl /usr/bin/gnome-shell -- and the log is full of the following line repeated **thosands of times per second**: gnome-shell: (../clutter/clutter/clutter-frame-clock.c:1143):clutter_frame_clock_dispatch: code should not be reached. It seems it takes 5-6% of CPU to solely log this. At this point I'm lost as there's only a single reference to this error in the Internet. AFAIU the code in question is https://github.com/GNOME/mutter/blob/main/clutter/clutter/clutter-frame-clock.c but I'm not in position to debug it. I won't ask if anyove has experienced it (but would appreaciate a solution of course :) ) -- but how to address it in general? File a bug? To where? Mutter or Gnome? Or Ubuntu? :/ My Mutter libraries versions:

$ sudo apt list | grep mutter

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

gir1.2-mutter-14/noble-updates,now 46.2-1ubuntu0.24.04.4 amd64 [installed,automatic]
libmutter-14-0/noble-updates,now 46.2-1ubuntu0.24.04.4 amd64 [installed,automatic]
libmutter-14-dev/noble-updates 46.2-1ubuntu0.24.04.4 amd64
libmutter-test-14/noble-updates 46.2-1ubuntu0.24.04.4 amd64
mutter-14-tests/noble-updates 46.2-1ubuntu0.24.04.4 amd64
mutter-common-bin/noble-updates,now 46.2-1ubuntu0.24.04.4 amd64 [installed,automatic]
mutter-common/noble-updates,noble-updates,now 46.2-1ubuntu0.24.04.4 all [installed,automatic]
mutter/noble-updates 46.2-1ubuntu0.24.04.4 amd64

My system:

$ screenfetch
                          ./+o+-       flash@flash-NUC12WSHi5
                  yyyyy- -yyyyyy+      OS: Ubuntu 24.04 noble
               ://+//////-yyyyyyo      Kernel: x86_64 Linux 6.8.0-51-generic
           .++ .:/++++++/-.+sss/`      Uptime: 1h 25m
         .:++o:  /++++++++/:--:/-      Packages: 2260
        o:+o+:++.`..

.-/oo+++++/ Shell: bash 5.2.21 .:+o:+o/. `+sssoo+/ Resolution: 1920x1080 .++/+:+oo+o:` /sssooo. DE: GNOME 46.4 /+++//+:`oo+o /::--:. WM: Mutter \+/+o+++`o++o ++////. WM Theme: Adwaita .++.o+++oo+:` /dddhhh. GTK Theme: Yaru-dark [GTK2/3] .+.o+oo:. `oddhhhh+ Icon Theme: Yaru \+.++o+o`-

.:ohdhhhhh+     Font: Ubuntu Sans 11
         :o+++ ohhhhhhhhyo++os:      Disk: 1.3T / 3.2T (40%)
           .o:.syhhhhhhh/.oo++o      CPU: 12th Gen Intel Core i5-1240P @ 16x 4.4GHz [80.0°C]
               /osyyyyyyo++ooo+++/     GPU: Iris Xe Graphics

`` +oo+++o\: RAM: 5654MiB / 31606MiB `oo++. ```