In Switch, you cannot make a connection between two non-folder flow elements, without having a folder in between.
For this reason and to save time, when dragging a connection between two non-folder flow elements, Switch automatically adds a folder in between and creates a double connection (from the first flow element to the folder, and from the folder to the second flow element).
You can see that a folder is added upon creating the connection as the drag line includes the outline of a folder between source and destination, and the cursor changes to "allowed".
This insertion of a folder does not take place if,
there is not enough room in between the two flow elements to insert a folder
inserting a folder does not result in valid connections