Check the stated list limit first
TVNZ describes My List as a place for saved shows, films and events, with a one-hundred-title maximum. At that limit, a new addition automatically removes the oldest item to make room. An older bookmark disappearing just after another title was saved can therefore follow the published list behaviour rather than a failed account migration or an episode disappearing from the service.
Use the bookmark control deliberately
On a show or film page, select the My List bookmark icon to add it; select it again to remove it. The website also offers additions from a tile hover or the large hero banner. Review the actual list before adding more items at capacity, and remove selections you no longer want rather than expecting an unlimited archive of every programme ever bookmarked.
Look in Continue Watching for unfinished playback
TVNZ separately defines Continue Watching as started but unfinished shows, episodes and films. Its tiles have progress bars, and the service synchronises progress across devices. If the aim is resuming an episode rather than finding a saved recommendation, use that row. An item’s presence in one section should not be used to infer the status of the other.
Prepare for a connected viewing session
TVNZ’s offline help says show downloads are not currently supported. Saving a title in My List therefore does not prepare a playable local episode for a disconnected journey. Its data-saving advice includes lower playback quality and Wi-Fi where possible. Use the list to plan what to stream, while arranging a connection for the actual viewing.