Exec driver inside lxc container gives "cgroup path must be set"

I run my nomad worker inside a Proxmox container.
Nomad itself works fine but when I try to run a task with the “exec” driver I get the following error: “cgroup path must be set”

Google literally bring up only one result, the source: nomad/executor_linux.go at d3a55915f5b92f406f0a2fa79e69385a8bc13da1 · hashicorp/nomad · GitHub

But from there I can not exactly figure out what is the issue. I guess my client is not reporting cgroup info correctly?
Any idea or where further to dig?

Edit: unique.cgroup.version is detected as v2

Hi @soupdiver,

I am noting that it seems you also raised this against the Nomad repo and discussion is already underway with Tim.

Thanks,
jrasell and the Nomad team

Yea, I thought it’s better for something that technical.
For anyone interested: Task using exec driver fails with "cgroup path must be set" · Issue #14797 · hashicorp/nomad · GitHub