T3rm1 ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiNDUwMmIzNDUz... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16186?atlOrigin=eyJpIjoiNDUwMm... ) HHH-16186 ( https://hibernate.atlassian.net/browse/HHH-16186?atlOrigin=eyJpIjoiNDUwMm... ) Duplicate entries in OneToMany relation after manual eagerly loading of entries ( https://hibernate.atlassian.net/browse/HHH-16186?atlOrigin=eyJpIjoiNDUwMm... ) Issue Type: Bug Assignee: Unassigned Attachments: bug.zip Created: 15/Feb/2023 06:24 AM Priority: Major Reporter: T3rm1 ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) I’m not sure if the title fits. I had trouble finding a good one. This bug leads to multiple duplicates appear in the list of a OneToMany relation that was initialized manually in order to prevent N+1 query problem. There are three entities, A , B and C. A < 1 1 > B B < 1 N > C A has one B, B has multiple C. Loading is configured as lazy. *Given situation* : I have 4 {{A}}which all point to the same B. This {{B}}has two C. So if I do {{a.getB().getCList()}}the size should be 2. This works out of the box with lazy loading. However, if I add the following query, in order to load all {{C}}into the cache and a prevent N+1 query problem, then suddenly each {{B}}has *eight* entries of C. List<A> resultNotNeeded = entityManager.createQuery(""" select distinct a from A a join fetch a.b b left join fetch b.cList where a in (:aList) """, A.class) .setParameter("aList", aList) .setHint(org.hibernate.jpa.QueryHints.HINT_PASS_DISTINCT_THROUGH, "false") .getResultList(); It doesn’t make a difference if I remove the distinct and query hint. {{aList}}is just the list of the four a entities. A test case is attached. ( https://hibernate.atlassian.net/browse/HHH-16186#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16186#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100216- sha1:a1e7611 )