18.04 gnome desktop randomly freezes

I have been using 18.04 for a few months and about every 2 days, there is random GUI freeze. It has happened during web browsing, coding and watching movies so I guess that it is not an application issue. It freezes completely including the cursor. I checked syslog and kernlog without any clues (last message is usually few mins before crash). Any recommendations to find out what's wrong? Atm I would appreciate any error message.

• GPU: AMD HD7970
• Driver: Mesa 18.0.5
• CPU: Ryzen 5

Thanks

Edit: running apt-get update and upgrade approx once per week.

Edit2: apt list --installed | grep 'gnome\|extension\|shell'

compiz-gnome/bionic,now 1:0.9.13.1+18.04.20180302-0ubuntu1 amd64 [installed,automatic]
gir1.2-gnomebluetooth-1.0/bionic,now 3.28.0-2 amd64 [installed,automatic]
gir1.2-gnomedesktop-3.0/bionic-proposed,now 3.28.2-0ubuntu1 amd64 [installed,automatic]
gir1.2-gnomekeyring-1.0/bionic,now 3.12.0-1build1 amd64 [installed,automatic]
gnome-accessibility-themes/bionic,bionic,now 3.28-1ubuntu1 all [installed]
gnome-bluetooth/bionic,now 3.28.0-2 amd64 [installed]
gnome-calculator/bionic,now 1:3.28.1-1ubuntu1 amd64 [installed]
gnome-calendar/bionic-proposed,now 3.28.2-0ubuntu0.18.04.1 amd64 [installed,automatic]
gnome-control-center/bionic-updates,now 1:3.28.1-0ubuntu1.18.04.1 amd64 [installed,automatic]
gnome-control-center-data/bionic-updates,bionic-updates,now 1:3.28.1-0ubuntu1.18.04.1 all [installed,automatic]
gnome-control-center-faces/bionic-updates,bionic-updates,now 1:3.28.1-0ubuntu1.18.04.1 all [installed,automatic]
gnome-desktop3-data/bionic-proposed,bionic-proposed,now 3.28.2-0ubuntu1 all [installed,automatic]
gnome-disk-utility/bionic,now 3.28.1-0ubuntu1 amd64 [installed]
gnome-font-viewer/bionic,now 3.28.0-1 amd64 [installed]
gnome-getting-started-docs/bionic,bionic,now 3.28.1-0ubuntu1 all [installed,automatic]
gnome-initial-setup/bionic-proposed,now 3.28.0-2ubuntu6.16.04.1 amd64 [installed,automatic]
gnome-keyring/bionic-updates,now 3.28.0.2-1ubuntu1.18.04.1 amd64 [installed]
gnome-keyring-pkcs11/bionic-updates,now 3.28.0.2-1ubuntu1.18.04.1 amd64 [installed,automatic]
gnome-mahjongg/bionic,now 1:3.22.0-3 amd64 [installed,automatic]
gnome-menus/bionic,now 3.13.3-11ubuntu1 amd64 [installed]
gnome-mines/bionic,now 1:3.28.0-1 amd64 [installed,automatic]
gnome-online-accounts/bionic-proposed,now 3.28.0-0ubuntu2.1 amd64 [installed,automatic]
gnome-orca/bionic,bionic,now 3.28.0-3ubuntu1 all [installed,automatic]
gnome-power-manager/bionic,now 3.26.0-1 amd64 [installed]
gnome-screensaver/bionic,now 3.6.1-8ubuntu3 amd64 [installed]
gnome-screenshot/bionic,now 3.25.0-0ubuntu2 amd64 [installed]
gnome-session-bin/bionic-updates,now 3.28.1-0ubuntu3 amd64 [installed,automatic]
gnome-session-canberra/bionic,now 0.30-5ubuntu1 amd64 [installed]
gnome-session-common/bionic-updates,bionic-updates,now 3.28.1-0ubuntu3 all [installed,automatic]
gnome-settings-daemon/bionic,now 3.28.1-0ubuntu1 amd64 [installed,automatic]
gnome-settings-daemon-schemas/bionic,bionic,now 3.28.1-0ubuntu1 all [installed,automatic]
gnome-shell/bionic,now 3.28.1-0ubuntu2 amd64 [installed,automatic]
gnome-shell-common/bionic,bionic,now 3.28.1-0ubuntu2 all [installed,automatic]
gnome-shell-extension-appindicator/bionic,bionic,now 18.04.1 all [installed,automatic]
gnome-shell-extension-ubuntu-dock/bionic,bionic,now 0.9.1 all [installed,automatic]
gnome-software/bionic-updates,now 3.28.1-0ubuntu4.18.04.1 amd64 [installed,automatic]
gnome-software-common/bionic-updates,bionic-updates,now 3.28.1-0ubuntu4.18.04.1 all [installed,automatic]
gnome-software-plugin-snap/bionic-updates,now 3.28.1-0ubuntu4.18.04.1 amd64 [installed,automatic]
gnome-startup-applications/bionic-updates,now 3.28.1-0ubuntu3 amd64 [installed,automatic]
gnome-sudoku/bionic,now 1:3.28.0-1 amd64 [installed,automatic]
gnome-system-log/bionic,now 3.9.90-5 amd64 [installed]
gnome-system-monitor/bionic-updates,now 3.28.2-0ubuntu1 amd64 [installed]
gnome-terminal/bionic-proposed,now 3.28.2-1ubuntu1~18.04.1 amd64 [installed]
gnome-terminal-data/bionic-proposed,bionic-proposed,now 3.28.2-1ubuntu1~18.04.1 all [installed,automatic]
gnome-themes-extra/bionic,now 3.28-1ubuntu1 amd64 [installed,automatic]
gnome-themes-extra-data/bionic,bionic,now 3.28-1ubuntu1 all [installed,automatic]
gnome-todo/bionic,now 3.28.1-1 amd64 [installed,automatic]
gnome-todo-common/bionic,bionic,now 3.28.1-1 all [installed,automatic]
gnome-user-docs/bionic,bionic,now 3.28.1-0ubuntu1 all [installed,automatic]
gnome-user-guide/bionic,bionic,now 3.28.1-0ubuntu1 all [installed,automatic]
gnome-user-share/bionic,now 3.18.3-3 amd64 [installed,automatic]
gnome-video-effects/bionic,bionic,now 0.4.3-1ubuntu1 all [installed,automatic]
language-pack-gnome-cs/bionic,bionic,now 1:18.04+20180423 all [installed]
language-pack-gnome-cs-base/bionic,bionic,now 1:18.04+20180423 all [installed,automatic]
language-pack-gnome-en/bionic,bionic,now 1:18.04+20180423 all [installed]
language-pack-gnome-en-base/bionic,bionic,now 1:18.04+20180423 all [installed]
language-selector-gnome/bionic-updates,bionic-updates,now 0.188.1 all [installed,automatic]
libgnome-autoar-0-0/bionic,now 0.2.3-1 amd64 [installed,automatic]
libgnome-bluetooth13/bionic,now 3.28.0-2 amd64 [installed,automatic]
libgnome-desktop-3-17/bionic-proposed,now 3.28.2-0ubuntu1 amd64 [installed,automatic]
libgnome-games-support-1-3/bionic,now 1.4.1-1 amd64 [installed,automatic]
libgnome-games-support-common/bionic,bionic,now 1.4.1-1 all [installed,automatic]
libgnome-keyring-common/bionic,bionic,now 3.12.0-1build1 all [installed,automatic]
libgnome-keyring0/bionic,now 3.12.0-1build1 amd64 [installed,automatic]
libgnome-menu-3-0/bionic,now 3.13.3-11ubuntu1 amd64 [installed,automatic]
libgnome-todo/bionic,now 3.28.1-1 amd64 [installed,automatic]
libgnomekbd-common/bionic,bionic,now 3.26.0-3 all [installed,automatic]
libgnomekbd8/bionic,now 3.26.0-3 amd64 [installed,automatic]
libnautilus-extension1a/bionic,now 1:3.26.3-0ubuntu4 amd64 [installed,automatic]
libpam-gnome-keyring/bionic-updates,now 3.28.0.2-1ubuntu1.18.04.1 amd64 [installed]
libreoffice-gnome/bionic,now 1:6.0.3-0ubuntu1 amd64 [installed]
libsoup-gnome2.4-1/bionic,now 2.62.1-1 amd64 [installed,automatic]
nautilus-extension-gnome-terminal/bionic-proposed,now 3.28.2-1ubuntu1~18.04.1 amd64 [installed,automatic]
network-manager-gnome/bionic,now 1.8.10-2ubuntu1 amd64 [installed]
network-manager-pptp-gnome/bionic,now 1.2.6-1 amd64 [installed]
pinentry-gnome3/bionic,now 1.1.0-1 amd64 [installed,automatic]
policykit-1-gnome/bionic,now 0.105-6ubuntu2 amd64 [installed,automatic]
thunderbird-gnome-support/bionic-updates,bionic-security,now 1:52.8.0+build1-0ubuntu0.18.04.1 amd64 [installed,automatic]

From the comments...

• we downgraded from bionic-proposed to main
• we restarted the GNOME Shell with ALT+F2, then r
• the computer should be rebooted at this time

So far the computer has been running fine!