I'm used to work with simple polygons and the vertex tool. But now the Vertex Tool doesn't show me the capability of adding new nodes in centerline neither move polygon's segments. The function just disappeared.
Now the vertex tool only gives me the option to move the existent vertices. There's no more the "+" symbol giving me the option to add it. But, otherwise, it still gives me the option to add a new vertex while at the end of a line: