lxc access error

After being using Proxmox (running with proxmox-ve: 8.2.0 (running kernel: 6.8.12-1-pve) / pve-manager: 8.2.4 (running version: 8.2.4/faa83925c9641325)) for almost two years it's not running stable anymore with regars to LXC containers which I'm running. What has changed then? Well, two months...