Comment # 57 on bug 110214 from Diego Viola

I contacted Thomas Dickey (maintainer of xterm) and he said this about the
issue:

drivers, or Xorg in general -

for instance the parts painting by XCopyArea
(used by xterm and some other applications)
may not be getting repainting-events

https://lists.cairographics.org/archives/cairo/2015-May/026284.html

or buggy acceleration features

https://invisible-island.net/xterm/xterm.faq.html#compiz_bugs