@Fraga, welcome.
@olek already linked you to a duplicate topic which discusses this issue in detail; too much detail to be honest. As such I'm going to give you a shortcut to the short workaround:
Basically, the problem is: Somebody accidentally translated icon names a while ago; the buggy applications were included in Ubuntu (MATE) 20.04 LTS; the bug was fixed; it's tough to update LTS versions of packages, so nobody patched the LTS versions of the packages for Ubuntu 20.04.1 and thus the problem continues to haunt some of us.
Plagiarized from the post I quoted above, here's the commands to rectify the issue, at least for the time being:
sudo sed -i '/Icon\[/d' /usr/share/applications/*.desktop
sudo sed -i '/Icon\[/d' /usr/share/mate/desktop-directories/*.directory
sudo update-desktop-database
This deletes the unnecessary and detrimental translations on the icon names for numerous MATE applications and desktop directories. If it works, you can thank @azardo.