So I thought may this was an isolated issue but I have encountered it during two different installs using two different devices.
After I run sudo apt-get upgrade, while all the necessary processes take place - the values representing time, date, workspace session all turn into characters like apostrophes, underscores etc.
I first experienced this when trying to update kali on an RPi 4 which faces other issues during upgrade however its difficult to say why the UI is affected.
Thought to try a regular kali build on VMWare and the issue persists on the VM as well.
Devices used:
Raspberry Pi 4 - 4GB and 8GB models using ARM image on kali.org
VM - running on VMWare using VMWare image on kali.org
Both are 64 bit architectures.
The issue happens after trying to update a fresh install (image obtained from kali.org with no additional changes or customisations)
I've attached a screenshot where if you look at the taskbar on the top - you'll see where there are supposed to be numbers representing workspace sessions (i.e. 1,2,3,4) are now ', ., ", -
You can also see to the top right where the time and date are supposed to be displayed, the characters display instead of actual numerical values representing time and date.
The screenshot is obtained from VMWare but it also represents exactly the issue I face on the ARM build as well after 'upgrading'.
FYI: I run sudo apt-get update before running sudo apt-get upgrade