Our default iconset is Pocillo which uses Moka to display stylish application icons.
We note in 18.10 & 19.04 more and more applications have changed their icon-name.
Moka needs to know about the name change. Otherwise the applications own icon will be used instead - this leaves an inconsistent menu etc.
So please have a look at your menu (switch back to Pocillo or Moka temporarily if you are using another icon-set)
If you see an icon that does have the “squarial” Moka shape please let us know.
Three pieces of information is needed - so have a look in
/usr/share/applications for the applications .desktop file
We need to know the application name and the value of the line “Icon=”. Also we need to know the package name you used to install the application.
So we are aware of the following applications that we are going to propose a fix for the upstream project:
File-Roller (archive manager)
GNOME System Monitor
GNOME Contacts (18.04)