incorrect indentation with 100% default settings on a new clean install

i just installed qt 6.6.0 and qt creator 11.0.3 (community), i uninstalled my old qt and creator before installing this one.

 
i now have a problem with the automatic indenting feature. it's creating an alternating pattern for all my indents like this:

private:

  int var1; //2 spaces

    int var2; //4 spaces

  int var3; //2 spaces

    int var4; //4 spaces

the default settings are supposed to create a consistent indent of 4 spaces.

there is a preview pane in: Preferences > C++ > ClangFormat tab.

typing the variables into the preview pane correctly indents with 4 spaces.

i do believe that all of my settings and preferences for qt creator are at the defaults because i deleted everything in %APPDATA%\QtProject

my settings are:
Edit > Preferences > C++ > Clangformat settings:
Formatting mode: Indenting only.
Current settings: Qt [built-in]

i have found that the problem goes away if you go to Preferences>C++>CodeStyle, and click the "Copy..." button to make a duplicate of the current settings, then change the BasedOnStyle to Microsoft.

i suspect that the default "Qt [built-in]" settings are broken, since making a copy of the settings and changing the BasedOnStyle fixes the problem.

the problem also goes away if i completely disable formatting with "Formatting mode: Disable."

steps to reproduce the problem are simply do a full clean install on a window10 PC and try making some variables as shown in a "QT widgets application" project. all of my settings are 100% the defaults as far as i know.