Hi,

GNU Emacs 27.0.50 (build 1, x86_64-w64-mingw32) of 2017-11-08

git master, check out 6/7 Nov

How to repeat the bug:

Emacs -Q

C-x b, then, C-g

The verson by 14 Oct git has no such issue.

Best Regards

Shuguang