InvalidMove: A node may not be made a sibling of itself.

[sentry]

Sentry Issue: STUDIO-E31

InvalidMove: A node may not be made a sibling of itself.
(3 additional frame(s) were not displayed)
...
  File "contentcuration/db/models/manager.py", line 210, in move_node
    self._move_node(node, target, position=position)
  File "mptt/managers.py", line 71, in wrapped
    return method(self, *args, **kwargs)
  File "mptt/managers.py", line 592, in _move_node
    self._move_child_node(node, target, position)
  File "mptt/managers.py", line 1070, in _move_child_node
    self._move_child_within_tree(node, target, position)
  File "mptt/managers.py", line 1149, in _move_child_within_tree
    raise InvalidMove(_('A node may not be made a sibling of itself.'))

[rtibbles]

I wonder if this is a result of repeated application of changes - if you tried to move a node to be a child of its own parent, I think it might give this error.