Extern: merging fails for is_referenced_by if both entities are created on the fly
extern: https://gitlab.com/linkahead/linkahead-crawler/-/issues/95
Merging two entities that are referenced by a third entity fails with this identifiable:
Experiment:
- date
Event:
- is_referenced_by: Experiment
- event_id
- Is fixed.
- Followup issues created if necessary