minikube node start logs unexpected first step

[lingsamuel]

Steps to reproduce the issue:

1. minikube start
2. minikube node stop xxx
3. minikube node start xxx

Full output of failed command:
No a failure, but strange (network options removed):

E1203 11:01:03.130387 1503395 register.go:125] unexpected first step: ""
👍  Starting node minikube-m02 in cluster minikube
🔄  Restarting existing kvm2 VM for "minikube-m02" ...
❗  This VM is having trouble accessing https://k8s.gcr.io
💡  To pull new external images, you may need to configure a proxy: https://minikube.sigs.k8s.io/docs/reference/networking/proxy/
E1203 11:01:14.403140 1503395 register.go:125] unexpected first step: ""
🐳  Preparing Kubernetes v1.19.3 on Docker 19.03.12 ...
    ▪ env NO_PROXY=localhost,127.0.0.0/8,::1,192.168.0.0/16,zju.edu.cn,tsinghua.edu.cn,ustc.edu.cn
E1203 11:01:55.040378 1503395 register.go:125] unexpected first step: ""
🔎  Verifying Kubernetes components...
😄  Successfully started node minikube-m02!