I can also share early feedback, that something has changed when comparing V3 vs V4 behavior in terms of when interceptors can be added (and I haven't found this documented anywhere). Migrating to V4 required changing when the interceptor is added

// recovery mechanism doesn't work, extra logs are being logged
.autoPersistedQueries(httpMethodForHashedQueries = <http://HttpMethod.Post|HttpMethod.Post>)
.addInterceptor(ApqLoggingInterceptor())

// passes tests
.addInterceptor(ApqLoggingInterceptor())
.autoPersistedQueries(httpMethodForHashedQueries = <http://HttpMethod.Post|HttpMethod.Post>)

I'm not yet sure what it changes under the hood, I recall V3 had some changes around that (things like: https://github.com/apollographql/apollo-kotlin/pull/4628), but I haven't caught up with the discussion, so for now I can only share my findings here 🙂