Looks like someone fucked up package dependencies somewhere.
I'm surprised they don't have some basic automated testing running in a VM after new package releases but I suppose they don't need it if they can farm that duty out to their free userbase.
Been a while since I used proxmox but that's the nature of a lot of those free/corporate type softwares. The free 'community' edition is pretty well a public beta that you can get forum level support for, or sometimes you can get paid support at some limited level.