After update to Nextcloud 31.0.2 the User, contacts and notify logo location changed to vertical bar, but "There is some kind of bug that overlaps it with the applications interface.
Something is wrong with your installation. The location did not change. Please fill out the support template or we’ll be unable to provide you with any assistance.
I managed to fix it by clearing the cache with these commands:
sudo -u www-data rm -rf /var/www/nextcloud/data/appdata_*/css
sudo -u www-data rm -rf /var/www/nextcloud/data/appdata_*/js
Then, I forced a browser cache reload with Ctrl + Shift + R, and it appeared correctly.
Thanks!