@Gus Welcome to the forum!
If you have not already done so, please ask your wife to log out and log back in to her Bitwarden app, and check if that helps.
Is she able to see any of the shared items (e.g., by searching for one of them)? If so, is she able to make edits to any of those items.
If she logs in to her Bitwarden account via the Web Vault (on a computer), is she able to see the collection and the shared items there?
There may be some kind of bug that is causing this — there was a similar report (from somebody using a Bitwarden extension on macOS) yesterday.