Choose a precise test entry
Note the film’s title and year so a remake or similarly named television series does not confuse the comparison. Google supports adding titles through several routes, but those actions still need the intended account context. Check the profile selector on each device.
A typical hypothetical mismatch is a phone browser using a work account while the television uses a personal account. The saving action can succeed in the browser without producing the expected household list. This is a context problem to establish, not proof that the programme has vanished from a provider.
Inspect the television’s row
Google’s help places the Watchlist row beneath the profile area on supported television interfaces. Select the intended profile and look for that one exact entry. If Apps only mode is enabled, consider its documented limits on Watchlist actions before expecting the usual controls.
Keep the diagnostic small. There is no need to expose a full private list to support or add dozens of titles to test one mismatch. A cropped image of the relevant title and a written account-context comparison usually communicates more clearly while revealing less personal viewing information.
Keep reminders separate from access
Once the entry appears, open its details and check the current provider options. A saved reminder is not an owned licence or a download. The film may still require the appropriate provider account or a transaction, and an old saved date does not preserve availability.
If the account matches and one deliberately saved entry remains absent, report the adding route, title, profile, mode and time of observation. Do not delete an entire watchlist or change service passwords as a first response. Those actions remove useful state without establishing why the one reminder is missing.