Like the following screenshot:

Steps to reproduce

1. Resize the terminal so that it has width 140
2. git clone https://github.com/lantw44/ceiba-dl
3. tig
4. :set vertical-split = yes
5. Hit Enter to show diff for the latest commit
6. Hit arrow down to jump to the next commit

The mis-layout can be observed on at least xterm, konsole and xfce4-terminal

System information

OS: Arch Linux x86_64
Packages:

ncurses 6.0+20170902-1
xfce4-terminal 0.8.6-1
vte3 0.48.3-1
konsole 17.08.1-1
xterm 330
tig-git 2.2.2.r190.gbd42c8b-1, which is compiled from commit bd42c8b

Fonts:
Dejavu Sans Mono Book 16pt on Konsole and xfce4-terminal
I guess noto-fonts is used for CJK characters
xterm uses its default font (?)