Personal list items endpoint returns fewer items than X-Pagination-Item-Count

Endpoint: GET /users/me/lists/{slug}/items/movies

Description:

When fetching all pages of a personal list, the total unique items returned is consistently lower than the value reported by X-Pagination-Item-Count.

Reproduction:

List: movie-lists (4,274 items per list metadata, 4,273 per items endpoint header)

Request: /users/me/lists/movie-lists/items/movies?limit=1000&page={1-5}

Pages 1–5 each return 1,000 / 1,000 / 1,000 / 1,000 / 273 items

Total fetched: 4,273

Unique IMDb IDs after deduplication: 3,669

The same 604 IMDb IDs appear on multiple pages

Retrying all pages multiple times yields the same 3,669 unique results consistently

Cache-Control: no-cache header makes no difference

The same list fetched via MDBList (which mirrors from Trakt) returns 4,258 unique items with zero duplicates

Expected: All 4,273+ items returned with unique IDs across pages

Actual: 604 duplicate entries across pages, 612 items completely absent from all pages