Included audio languages may differ by country or country-like region. What is your country (as set for your Apple ID account)? Did you buy it in the same country as what you are trying to watch it in now? If you emigrated, then a different region version of the content may apply now, with different audio track languages.
Also note that the line for “original audio” in the content description does not mean that it is included. Included audio tracks are listed separately. Some countries have a habit of defaulting to dubbed content.
While a supplying studio can bring a new upload with minor alterations at any time, it is quite uncommon. When it happens, it is more likely to include more features, rather than taking away.
Please specify the title.
Please specify your country or region.
For issues with specific purchased titles, that cannot be solved from the user side, please contact the iTunes Store staff.