Save the point both people reached
Use the shared viewing position, not the furthest position on any individual profile. If both viewers stopped at 47:20 but one later watched to 55:00, the joint resume point is still 47:20. Record a non-spoiling scene cue in case the displayed time varies across devices.
Decide whether the film still belongs on the active list
Ask both viewers whether they actually want to finish. A polite “maybe later” need not keep a film at the top for weeks. Write “both want to finish Thursday” or “Alex may finish alone” to give the next chooser a clear decision. Keep an unfinished title separate from a watched entry.
Resume when the time stamp does not match
If one person continues alone, update the note rather than marking the film finished for the household. Ask before explaining later scenes to the other viewer. Their next watch can resume from the shared stopping point.
If the service begins at a different time because this edition has a longer introduction, use the scene cue and rewind a little rather than skipping into unseen material. If the edition has changed substantially, ask whether a brief recap or a restart is preferable before deciding for the other viewer.