Opening a CMakeLists.txt file syncs in <File System> instead of the project tree

When I open Qt Creator source code in Qt Creator 4.15.0-beta1 then issue <cmo CMakeProjectManager> I will get the corresponding CMakeLists.txt opened, but in the Projects pane the CMakeLists.txt that gets synced is the one in <File System> and not in the project view.

If I open a source file next to the CMakeList.txt then the Projects pane gets synced to the correct project view.

Opening a CMakeLists.txt should open also in project view and not in <File System>.