Inspect the local metadata source before repeating a refresh
If a poster or description returns to an unwanted value after a refresh, first identify whether the media folder has an NFO file. Jellyfin’s metadata documentation says local NFO information is fetched ahead of remote metadata sources. A remote provider being correct therefore does not establish which source the server used for that particular library item.
Read the field and artwork precedence
Jellyfin also says that when several NFO tags map to one internal field, the last tag has priority. Its artwork rules prefer paths or URLs defined in NFO over remote image providers and ordinary images in the media folder, using the first reference for an artwork type. These details can explain why replacing a nearby image or refreshing a remote description has not produced the expected result.
Review one authorised item without erasing its history
For example, an administrator can preserve the existing NFO, inspect the relevant description and artwork entries, and compare them with the intended source. Check the exact edition and provider identifier before replacing any metadata. Make one deliberate correction through the supported workflow and inspect the same item afterwards. Keep a recoverable copy of hand-edited information that matters to the library. Do not repeatedly delete the whole library or rename media simply to test a source-priority question. Report the local-versus-remote source and affected field when seeking help, rather than saying only that refresh does nothing.
Questions, answered
Can a correct remote poster lose to an NFO artwork reference?
Yes. Jellyfin documents higher priority for artwork paths and URLs defined in NFO files.