Bug Unity Hub does not recognize a project version change

It seems that Hub only checks the project versions on launch and never again. If you checkout a different branch of the project that is using a different version of Unity, Hub tries to open it with the wrong version, even if the correct/matching version is installed.

Steps to reproduce:
1. Clone a project that is using git and has been updated to newer version of Unity during development.
2. Checkout the most recent master commit that is using a recent Unity version.
3. Add the project to Hub and open it. It will open it with the recent Unity version.
4. Close the Editor.
5. Checkout an older commit that is using an older Unity version.
6. Go back to Hub. Notice that the project version was not updated.
7. Open the project.

Expected result:
Hub opens the project using the already installed and matching older Unity version.

Actual results:
Hub will ask you if you want to upgrade the project to the newer version.

Suggestion:
Update the project version when the Hub window gets focus.