I have a Plex server on a Synology NAS and Infuse running on my Mac (Haven’t checked the Apple TV yet).
Sorting of collections seems to be completely messed up at the moment. At two level, firstly of the collections in the library as a whole, and secondly in the items within the collection.
Problem 1: I would expect collections to be sorted using the name of the collection. However it appears that the sorting of the library in fact uses the title of the first movie in the collection.
But even that isn’t consistent. For example I have a collection called “The Wizarding World” which holds all the Harry Potter and Fantastic Beasts movies. Currently that collection is appearing between Erin Brockovich and Field of Dreams, which means it’s not sorting by either the name of the collection or the title of the first movie in it. It appears to be sorting by either the last film in the collection or the first film when title sorted (Either way Fantastics Beasts).
Problem 2: Infuse appears to be completely ignoring the sorted list sent from Plex and just sorting by year.