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There may be an issue in your flow definition. You can use an API call to query the flow definition from Salesforce. Examine the result to determine whether the flow definition contains Salesforce content that needs to be translated in Salesforce. Refer to How do I query a flow definition for more information.
The following image shows the results of a flow definition query. If the flow label is supposed to be translated, the area in the square would be in your desired language. If it is in English, then you know your Salesforce data has not been translated completely, and further action is needed.
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