I’m not sure which one but update 6.4.2 or 6.4.3 made Unbreakable, Split, and Glass stop showing up as a Collection on my AppleTV. Those 3 movies were automatically listed in the Collection section as “Eastrail 177 Collection” prior to those updates. The movies weren’t deleted. They just no longer appear as a collection.
It looks like this collection was removed from TMDb.
TMDb classifies Collections as ‘true sequels’ and Eastrail 177 is one example they cite as something which should not be grouped.
For example, the “Eastrail 177” trilogy and the Cloverfield films do not belong in a collection. The Man of Steel Collection is only for the Superman sequels and should not be used as the DC Extended Universe. Similarly, each film series in the Marvel Cinematic Universe, including The Avengers, has its own collection.
Thanks for the quick reply.