Screen corruption - solid but jagged black rectangles - in Notepad, Word, on Win 10 on Linux

[WhatHaveYou]

I have the problem described in this old, locked post. For, in Word or Notepad, in a Windows 10 Home guest, sometimes when I move the caret in Notepad or Microsoft Word there is screen corruption. The corruption takes the form of somewhat jagged black rectangles. The problem is intermittent. I have the latest release verson of Virtual Box. My host is Linux Mint 19.1 x64 Cinnamon. The native hardware is a powerful laptop - a Thinkpad X1CG6, with Intel graphics. The VM has plenty of resources allocated to it. So far, I've seen the problem only when the laptop is on battery power.

Can anyone help?

EDIT: There is some reason to think that undervolting was the problem . .

[andyp73]

Attaching an image that shows the problem and also the log file from the guest might help us to help you.

-Andy.