Issue with new fleeting plugin - invalid memory address or nil pointer dereference

I've written my own fleeting-vsphere plugin and tested all functions. But when i try to use it with gitlab runner the following happens

Added job to processing list                        builds=1 job=471304 max_builds=1 project=15674 repo_url=<redacted>
Failed to requeue the runner                        builds=1 max_builds=1 runner=VCxV9LZpU
Running with gitlab-runner development version (HEAD)  job=471304 project=15674 runner=VCxV9LZpU
  on DESKTOP-4M70UBK VCxV9LZpU, system ID: s_82e5e82688bd  job=471304 project=15674 runner=VCxV9LZpU
Resolving secrets                       job=471304 project=15674 runner=VCxV9LZpU
Preparing the "docker-autoscaler" executor  job=471304 project=15674 runner=VCxV9LZpU
Preparing instance...                               job=471304 project=15674 runner=VCxV9LZpU
WARNING: Job failed (system failure): panic: runtime error: invalid memory address or nil pointer dereference
  duration_s=0.00057292 job=471304 project=15674 runner=VCxV9LZpU
Appending trace to coordinator...ok                 code=202 job=471304 job-log=0-532 job-status=running runner=VCxV9LZpU sent-log=0-531 status=202 Accepted update-interval=1m0s
Updating job...                                     bytesize=532 checksum=crc32:2c6a55d4 job=471304 runner=VCxV9LZpU
Submitting job to coordinator...ok                  bytesize=532 checksum=crc32:2c6a55d4 code=200 job=471304 job-status= runner=VCxV9LZpU update-interval=0s
Removed job from processing list                    builds=0 job=471304 max_builds=1 project=15674 repo_url=<redacted>
WARNING: Failed to process runner                   builds=0 error=panic: runtime error: invalid memory address or nil pointer dereference executor=docker-autoscaler max_builds=1 runner=VCxV9LZpU

It appears it crashes right after the "Preparing instance.." step. I successfully able to connect with username and password set in config toml via ssh.

My config.toml is following:

  [runner.docker]
    image = "busybox:latest"
  [runners.cache]
    MaxUploadedArchiveSize = 0
  [runners.autoscaler]
    capacity_per_instance = 1
    max_use_count = 1
    max_instances = 10
    plugin = "fleeting-vsphere"
    [runners.autoscaler.plugin_config]
      vsphereurl = "<redacted>"
    [runners.autoscaler.connector_config]
      username = "user"
      password = "Passw0rd"
      use_static_credentials = true
      timeout = "1m"
    [[runners.autoscaler.policy]]
      idle_count = 1
      idle_time = "30m"

Any idea to further troubleshoot?

/cc @josephburnett