I spent a little bit of time of this, so in case someone runs into the same issue it could help.
I was using the qubes-template-builder with F32 minimal to create an archlinux template,
“make template” threw an error so I had to make a little modification to get it built:
It was breaking due to a dependency issue - so the fix was to comment out “font-bitstream-speedo” in the qubes-src/builder-archlinux/scripts/packages.list
So then the template was about to build, and install
But another issue was the qubes-gui-common etc files for the thunar dropdown to copy/view etc between VMs were unavailable (apparently due to some package conflicts).
The solution without downgrading any packages was:
In thunar file manager, click view > configure custom actions, and recreate the menus from a working vm, like for like.
Then if you have more arch vms, you can take this file from /home/user/.config/Thunar/ and copy it to any other affected arch templates/appvms.
Hope this helps someone.