Desktop shortcuts disabled after upgrade to 20.04.3 now open in text editor

Additional information.
lsb_release -a:

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.3 LTS
Release: 20.04
Codename: focal

screenfetch -n:
 cmeo@rodan
 OS: Ubuntu 20.04 focal
 Kernel: x86_64 Linux 5.4.0-81-generic
 Uptime: 28m
 Packages: 2814
 Shell: bash 5.0.17
 Resolution: 1920x2160
 DE: Unity 7.5.0
 WM: Compiz
 WM Theme: Ambiance
 GTK Theme: Ambiance [GTK2/3]
 Icon Theme: ubuntu-mono-dark
 Font: Ubuntu 11
 Disk: 136G / 455G (32%)
 CPU: Intel Core i7-6500U @ 4x 3.1GHz [51.0°C]
 GPU: Mesa Intel(R) HD Graphics 520 (SKL GT2)
 RAM: 3545MiB / 15480MiB
Digging into this further, I found that there are .desktop files that are working and some that are not.

The .desktop files which don't work were created by playonlinux. Here is an example:
[Desktop Entry]
Encoding=UTF-8
Name=WarInTheEast
Comment=PlayOnLinux
Type=Application
Exec=/usr/share/playonlinux/playonlinux --run "WarInTheEast" %F
Icon=/home/cmeo/.PlayOnLinux//icones/full_size/WarInTheEast
Name[fr_FR]=WarInTheEast
StartupWMClass=WarInTheEast.exe
Categories=
X-Desktop-File-Install-Version=0.24

And here is one that does work:
[Desktop Entry]
Type=Application
Name=Arduino IDE
GenericName=Arduino IDE
Comment=Open-source electronics prototyping platform
Exec="/home/cmeo/arduino-1.8.12/arduino"
Icon=arduino-arduinoide
Terminal=false
Categories=Development;IDE;Electronics;
MimeType=text/x-arduino;
Keywords=embedded electronics;electronics;avr;microcontroller;
StartupWMClass=processing-app-Base

I am closing the bug after finding https://askubuntu.com/questions/1197990/how-to-add-shortcut-starter-to-file-program-or-folder-in-the-desktop-or-menu

This is a feasible though not perfect workaround. It seems desktop shortcuts are more or less deprecated in the old form.

Procedure:
sudo desktop-file-install [some .desktop file which worked before]

install and run alacarte, and create a new item. Provide the path used in the .desktop file as is.

The item will now appear in Dash with its icon (though not anywhere else) and run. This will have to do by the look of it.

Hmm I don't seem to be able to close it. Someone else will have to.
Still doesn't explain why some shortcuts kept working and others didn't, but there you go.