Whenever I install an update the theme resets to the dark one.
I always have to go into the preferences and put back the light gray one.
 
I can live with this, but what worries me is - are any other preferences being reset?
There's a lot of them and I don't remember what all I have set.
 
Note: I download at work and install at home, so I do not use the Command Center (if that makes a difference).

I had made my own theme.
After an update via Command Center my theme is NOT reset to Tungsten. Nothing changes.
Remember that the themes can be also saved in the lenses.
 

If you are using the Mercury theme, it is changed to Tungsten by the installer.
 
Also, the installer will add some default paths to the VST settings, if you removed them.
 
These are the only changes in the settings made by the installer I'm aware of.

Use a your own lens as default. I saw my version change to Tungsten then magically flicked to back to my Mercury theme after installing latest update.