Sometimes, when Vagrant VM in Virtualbox can stuck in this state and you cannot resume execution at all.
Turns our it happens only when your host machine hibernated or suspended while Vagrant VM was running. And that also should co-oncide with Ubuntu’s systemd missing some dbus event.
You can notice that after such failed restore your network is also missing and you need to restart it manually.
Easy – suspend and wake up your host once again and VMs will be in a running state automatically.