Why is my Google Pixcel C stuck on "waiting for fastbood command"?

[AC Question]

I have 10 Google pixel C tablets. 7 of them work great but 3 have trouble connecting to Wi-Fi. Upon rebooting them, when I powered on one of the tablets, it went to "waiting for fastboot command" and has been there for 4 hours now. Any ideas or reasons this would happen. Also any ideas on the Wi-Fi connection would be helpful too.