I was surprised to see these changes lately again too when collectios started to diseppear from my Kodi library. While many of these changes are fine there are some that are surprising to me. For example I don't exactly understand why the Eastrail 177 trilogy is not considered as a collection anymore since it fits this: "As a general rule, a sequel is a film which centers around the same main characters and continues the story of an earlier film. The protagonists evolve and are aware o the events that happened in the earlier films."? While they are not numbered and the second movie, Split, is very much a stand alone part they still tie together quite strongly and the last part, Glass, is in my opinion a clear sequel to both Unbreakable and Split. They have the same characters, same actors, same timeline, same backstory, same writer and same director and the characters even remeber the past events (Split obviously has only the new Beast character except for the end so there isn't any past events to present but the story of Glass really does not make sense without it or Unbreakable). For Cloverfield I understand the following because they have no relation except for the name: "For example, the "Eastrail 177" trilogy and the Cloverfield films do not belong in a collection.".

Glass, is in my opinion a clear sequel to both Unbreakable and Split.

Yes, exactly. So, should we create a collection with Unbreakable and Glass or one with Split and Glass. We can't have both collections, or one with all three movies. That's the dilemma and the official reason why this proposed collection is not a fit with the current collection rules.

@lineker said:

Glass, is in my opinion a clear sequel to both Unbreakable and Split.

Yes, exactly. So, should we create a collection with Unbreakable and Glass or one with Split and Glass. We can't have both collections, or one with all three movies. That's the dilemma and the official reason why this proposed collection is not a fit with the current collection rules.

I feel that in this case the rules are too strict and these three should be part of a collection as even the creators themselves have said that they are a trilogy. ProjectVRD has explained why much better over here: https://www.themoviedb.org/talk/5e2247a9397df000169989d2