I have the no subscription installed and this morning it looked like there was a large update so I tried updating but only got caught in a loop getting a lot of "Ign:1 through 21" messages". I ran
nano /etc/apt/sources.list.d/pve-no-subscription.list
and nothing was there. I added deb http://download.proxmox.com/debian/pve bookworm pve-no-subscription
,ran apt-get update
and all was well again. How could that have gone missing? Updates in the past have been flawless.