Even thought I know that you should install signal in a different way I used it for testing purpose:
In the templatevm (fedora-32) I installed signal-desktop via
sudo snap install signal-desktop
and after several reboots I still do not find signal in related AppVMs.
Even if I create a new AppVM I get
[user@signal-tmp ~] which signal-desktop /usr/bin/which: no signal-desktop in (/home/user/.local/bin:/home/user/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/var/lib/snapd/snap/bin) [user@signal-tmp ~]
Signal is in the application menu of both templatevm and appvm which seems weird. I also extended memory so that should not be the reason and signal is running fine in template-vm.
I encounter this issue just in some cases (e.g. slack works fine im appvm).
Do you have an idea how to resolve this?