Changing instance configuration hangs on start with VirtualBox

[Sploder12]

Describe the bug
Occasionally, changing the configuration of an instance then starting it will result in the start hanging. After restarting the daemon, the instance will be in the suspended state and be started normally.

To Reproduce

1. Launch an instance
2. Stop the instance
3. Change CPUs from 1 to 2
4. Start the instance
5. Observe starting forever
6. Restart daemon/machine
7. Observe instance in suspended state
8. Start instance
9. Observe instance finish starting

Expected behavior
The instance starts normally without a hang.

Logs

4:14:56 PM [new-rook] Waiting for SSH to be up
4:20:13 PM [new-rook] SSH session disconnected
4:20:13 PM [new-rook] Caching new SSH session
...
Repeats ssh disconnect and cache once every 20 seconds.

Additional info

• OS: Windows 10 Home
• multipass version: 1.14.1, 1.50 RC2
• multipass get local.driver: VirtualBox

Additional context
Is not guaranteed to happen. The daemon will give up ("Waiting for daemon") after 5 minutes.