Manager support Google Kevin kirk in response to a couple messages about phantom reboots grombala Pixelbook said that the issue has been resolved.
To end with random reboots, you need to update device software to version 10323.65.7 65th stable build of Chrome OS.
At least since March of this year, some users grombala Pixelbook have problems with phantom restarts. One of the messages about the problem on the Google forum mentioned the frequency of reboots every 1-10 minutes. Another message says about 10 reboots a day.