System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: Intel(R) HD Graphics 4600 Intel 4.3.0 - Build 20.19.15.4835

Blender Version
Broken: version: 2.83.2, branch: master, commit date: 2020-07-09 05:50, hash: rB239fbf7d936f
Worked: (newest version of Blender that worked as expected)

Short description of error
As the title says, all text disappears when the theme is changed. Restarting Blender brings it back, until you change the theme again.

Exact steps for others to reproduce the error
Click on Edit, Preferences, Presets, select a theme from the drop down menu, voila, textus disappearus.
Based on default startup.