I'm seeing the same too. Been running OPNsense for about a year in a Proxmox environment and it's been flawless. I'm pretty sure it's since the last system update (I update on a daily basis). I have OPNSense in a 2 node High Availability setup on two different proxmox servers and both firewalls die at similar time. They are 'up' but the CPU is so busy the firewalls stop passing traffic.
I'm pinning all my hopes on it being fixed in the next update.
I'm pinning all my hopes on it being fixed in the next update.