Can't write multiple records with same relational ID

The input "Records" cannot insert or update a record which is referring to different referenced records via propostaId at the same time. To create a reference to a related record, include either a relationship reference or the required common field value for "propostaId". Location of conflicting changes: GC Document [1]
= a!forEach(
  pv!documentos,
  a!update(
    fv!item,
    'recordType!{GC Documento .fields.{389973d7-a3f2-4ce3-aafb-9c2021e72ce9}propostaId',
    pv!idProposta
  )
)
I can't find anything about this error at all

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