The line spacing setting in current profile of gnome terminal is default value 1.0. Everything, include powerline symbols, is rendered well before. But recently, the powerline symbols’ rendering is broken as below.
Also, and we should double-check this, but the guifont etc. options that you are using in your vimrc are only used in Gvim as far as I know. In a terminal, vim just picks up whatever font settings the terminal uses.
My gnome-terminal font is system mono font set by gnome-tweak-tool, Source Code Pro Medium.
In the link, they discussed as below:
Setting the system language to zh_CN will trigger the issue. They think it’s the line height, decided by CJK fonts, is higher than before and makes powerline symbol render broken.
Then I tried on my laptop. When switch system language to English, gnome-terminal do render better. The line height changes to normal appearance, but still have some defects, especially the powerline symbols. So I’m using English UI and gnome-terminal is much better now.