Opening Editor from Source (2nd time) Requires Rebuilding Entire Engine?

Hello,
I am following this tutorial to build from source and open the UE5 editor:

I followed the steps for opening the editor, and it worked just fine. From the editor I created a project, and the editor auto-closed.

However, I decided I wanted to change the specs of the project, so I did the same thing from the above tutorial, for opening the editor. I right-clicked on ‘UE5’ under ‘Engine’ and clicked ‘Set as Startup Project’. Then I right-clicked and selected ‘Start New Instance’ under ‘Debug’, and VS2022 started re-building the entire engine from scratch. I saw ‘Building ~5700 actions with 4 processors’.

What? Does this mean I have to rebuild the entire engine every time I open the editor? That seems insane and impractical. I think it’s more likely I did something wrong. What may have caused this to happen?