set
[BackwardCompatibilitySettings]
AdvancedObjectRelationList=enabled

- create an object X with a relations attribute, fill the relation with 1 target object, Y, and publish.
- open the object X in the backend, the Relations tab should have 1 relation

(use a second tab to make navigation easier. using 2 tabs has no effect on the issue at all)
- In a new tab, edit the object X. Within the object relations field, edit the related object Y. trigger eZ Autosave to fire.

- back In the first tab, clear caches using the right toolbar. Notice how object X no longer has any relation in the Relations tab.

- In the second tab, discard the draft, close the tab

- in first (and now only) tab, reload the full view of object X. the relation to Y does not show anymore.

as secondary tests:
- open X for edit. check that Y is still in the relations list
- open X in a front end. check that Y shows as a related object.