UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce the problem:
If you open the following shortcut:

#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Terminal=false
Type=Application
Name=Google Calendar
Exec=/usr/bin/chromium --profile-directory=Default --app-id=kjbdgfilnfhdoflbpgamdcdgpehopbep
Icon=chrome-ejjicmeblgpmajnghnpcppodonldlgfn-Default
StartupWMClass=crx_kjbdgfilnfhdoflbpgamdcdgpehopbep

It does so as a separate instance, with its own icon separated from the Chromium one.

But if you change the exec option to:
/usr/bin/chromium --profile-directory=Default --app=calendar.google.com/calendar/r

It does in the same Chromium icon.

It would be nice that it could be launched in a different instance too. It would allow having web apps preinstalled in Linux systems, or system wide.

What is the expected behavior?

What went wrong?
N/A

Did this work before? N/A 

Chrome version: 65.0.3325.181  Channel: stable
OS Version: 
Flash Version: