The commit that caused this change in behavior is HHH-13465 Allow inlined access to the PersistenceContext for internal… · hibernate/hibernate-orm@2e81c32 · GitHub
Since SessionStatistics doesn’t say anything explicit about what should happen when the session is closed, this is IMO a valid change, but if you want to discuss this further, I would suggest you ask Sanne Grinovero in our Zulip chat directly.