Unexpected error while trying to map XML

I'm trying to import an object from an XML file. The XML file contains a main object and some associated objects. For the mapping of associated objects in the XML, I'm using a microflow (option: 'to obtain an object' = 'Call a microflow'). The microflow retrieves the associated object from the Mendix application by searching for a matching 'Name'-attribute. The option 'If no object was found' of the mapping is set to 'Ignore'. I would expect the mapper to search for the object and linking the found object to the imported main object (if an object was found). Instead an error is thrown. The error states that the associated object already exists. I do not know why this happens, becaus I do not try to create a new associated object (first try to retrieve and if no object was found, ignore). Is this a bug or am I doing something wrong? Thanks!
1 answers

This error 'De gebruikersnaam is al in gebruik' seems to be a data validation error that you defined yourself in your domain model. Can you check this?