Merge Translations Error

When merging the translations from one source to another in the zanata Web Platform we get the following exceptions:

ERROR [org.hibernate.engine.jdbc.batch.internal.BatchingBatch] HHH000315: Exception executing batch [could not execute batch]
ERROR: Duplicate entry '0-202972' for key 'PRIMARY'
ERROR: Duplicate entry '0-211663' for key 'PRIMARY'
ERROR: Duplicate entry '0-213789' for key 'PRIMARY'
ERROR: Duplicate entry '0-217610' for key 'PRIMARY'
ERROR: Duplicate entry '0-225771' for key 'PRIMARY'
ERROR: Duplicate entry '0-247004' for key 'PRIMARY'
ERROR: HHH000315: Exception executing batch [%s]
WARN [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] SQL Error: 1062, SQLState: 23000
WARN [org.zanata.model.HTextFlow] null locale, assuming 'en'
WARN [org.zanata.service.impl.MergeTranslationsServiceImpl] exception during copy text flow target
WARN: SQL Error: 1062, SQLState: 23000
WARN: exception during copy text flow target
WARN: null locale, assuming 'en'

This results in an incomplete merge. Do you have any solution or workaround for this problem? BR Erika Dautz