Bug: If a user tries to make changes in the main branch of a branched project, they should be warned that their changes will be discarded.

Hello Daniel, 

I first want to apologize that this inconvenience happened. I know it can be frustrating to lose changes and the work you've put into the project thus far. We do have a warning in yellow when a user opens a project. Unfortunately, it can be dismissed which might have happened in your case. I can send along a note to our Product team that perhaps this warning should not be dismissible.