If manual sorting is turning on automatically when you enter a folder, then you must have done this (from the page you linked):
You can also turn on the Sorting Options / Manual sorting option on the Display tab in the Folder Options dialog. Obviously as a folder options setting, this mode can also be made permanent by saving the folder format.
You can turn it off again in the same place and re-save the folder format to undo that.
You can see all your saved folder formats via Preferences / Folders / Folder Formats, if you want to check which have manual sorting turned on and turn it back off in them.
Or you can follow Folder Formats: Quick Guide to apply the same format to all folders and remove any custom formats for specific folders.