The unified-library grid unmounts when you open an item's info/show/season page
and remounts as a NEW element on Back. The IntersectionObserver effect keyed only
on [hasNextPage, isFetchingNextPage, fetchNextPage] — none of which change across a
pure navigation — so it never re-ran: the observer kept watching the detached old
sentinel node and fetchNextPage never fired again, leaving the feed frozen at the
already-loaded pages (e.g. 80/1227) even though more exist. Intermittent because a
coincident isFetchingNextPage toggle around the nav could re-run the effect.
Fix: observe via a callback ref (state) instead of useRef, so the effect re-runs on
every sentinel mount/unmount and always watches the live node.
peter
9a00bd8836