Please see this reply from a previous report.

Do you know if the dates stored are meant to represent Eastern Time then?

As a developer using TMDB's API, I assumed these were GMT. In which case, 9PM ET is 1AM GMT the next day. So, by setting the air date on (say) the 4th because it is released at 9PM ET you get:

• The date stored in the database as the 4th (assumed to be 12AM GMT)
• That's equivalent to the 3rd at 8pm ET Which is 25 hours earlier than intended. For me, it means notifying many of my users a day earlier about a new episode.

Ultimately I think that's the reason Apple says the release date is Friday. They use the latest day at which they release, across all time zones so that users know for sure when they can view a show. For people in the UK, the show is very much release on Friday. I feel like TMDB should reflect the official release date in this case. Hopefully that makes sense.

The dates stored in the database are the dates in the origin country of the series.