Why does Windows 10 keep resetting my folder view settings to General Items?

You have already tried applying a template broadly and rebuilding the view cache, but individual folders still revert to General Items after closing Explorer. “Apply to Folders” applies a view to folders of the same template; it does not guarantee that every folder will keep a template forever. Windows can re-evaluate a folder when its contents change, and profile-specific Explorer settings or a shell extension can interfere. First open the affected folder, right-click its background, choose Properties, open Customize, select the intended “Optimize this folder for” template, and apply it to subfolders only when appropriate. Then restart Explorer once and test the exact folder after a sign-out. If only one Windows account is affected, test with a new local account before changing registry entries; that separates a profile configuration problem from a system-wide update or permissions issue. Avoid deleting shell-bag data until this comparison confirms it is necessary.