PyCharm opens the wrong project

When I click File > Open > [browse to my_project directory] > OK

Another project is open, but not the one I requested. What for?

The window title points to my_project

, but the project files on the left are owned by another project.

The same thing happens when I use File > Open Recent > my_project

I tried to do File > Invalidate Caches/Restart

, but I have the same behavior.

I am using PyCharm Professional 2017.1.2

onUbuntu 16.04.2 LTS 64-bit

Is this a reported bug? How to fix it?