AUR seams to update prematurely to version 6.0.8 while pop.com still list 6.0.4 as its current release.
-> Downloading pop_6.0.8_amd64.deb...
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 132 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
curl: (22) The requested URL returned error: 404
==> ERROR: Failure while downloading https://download.pop.com/desktop-app/linux/6.0.8/pop_6.0.8_amd64.deb
Aborting...
error downloading sources: pop-bin