Updated the Kali Linux and as a result, updated the Gnome to version 3.20.1, but is now appearing in the title bar (and other places in some Gnome applications) squares instead of letters. How do I fix this?
I found an answer over at AskUbuntu. It looks like some fonts are missing and need to be re-installed. Here's the steps from that answer:
sudo apt-get install msttcorefonts sudo fc-cache -fv
Reboot your machine and it should have the title bars fixed.