> Also IDs aren’t required for cache updates, only the typename.

this is very inacurate. The problem happens when an items is cached with an ID and then another GraphQL request tries to cache it without and ID or vice versa. This is where the apollo-cache-inmemory blows up with an error like this: https://api.media.atlassian.com/file/f82c0ee8-2412-4f1b-8027...

There's even a test for this unfortunate behavior: https://github.com/apollographql/apollo-client/blob/master/p...