I have tried transforming an artifact from the tracker equivalent of "task" to its parent tracker (equivalent to "user story").
I filled some fields, like "Initial effort", "Remaining effort", etc. and created a new changeset after moving the artifact successfully.
After having clicked on "Add to top backlog", I could not see my new "user story" in the top backlog.
I wanted to add the new story to my release, sprint and to its parent epic. Since I could not do it via the planning view, I persevered and added manually the artifact links, successfully.
However, after having manually edited the artifact links, I still can't see my story anywhere, neither in planning nor taskboard, nor overview. AND it's also not visible in the release, sprint, or epic's artifact links, despite having been added there successfully.
I am now unable to remove this broken "user story" in the UI.

I noticed that its "Rank" field is empty, since most APIs order artifacts by rank, it could explain why this story is now invisible ?