From: Folder Formats: Detailed Guide
If you are viewing a directory and make changes to the folder format (e.g. by switching to thumbnails mode, or adding, removing or sorting by a column), then your change will continue to be applied, within the current window only, when you go to other folders, unless those folders trigger an explicit format change.
You can use the Folder Formats menu to explicitly reset the format. (Alternatively, just close the current window and open a new one, which is often quicker.)
To save a special format for a folder, open Folder > Folder Options and click the Save button.
Or you can create a Path format under Preferences / Folders / Folder Formats, which is also where you can review and edit all similar formats.
After saving a new format, it's best to close any open listers and test in fresh ones to ensure you're testing what happens with a new window, without any remembered state due to the Temporary Formats of Cached Formats functionality described in the FAQ.