We have such problem in report edit screen when trying add or edit parameters. Idk where is problem because there are no duplicate values in any field (there are three of them - name, code and link to other entity, which is null or have unique links). Cuba version 7.2.15
IllegalArgumentException: Multiple entries with same value: Материал РСО (rtneo_Material)=rtneo_Material and Material (rtneo_Material)=rtneo_Material
but Material is name of entity, and Материал РСО is its definition in messages. In data model it isnt used with Material alias.