The information provided is not sufficient to provide a definitive answer. It would be beneficial to create a support case at https://gateway.sdl.com/ There could be a variety of reasons causing the issue.

• The XML files were exported from another Passolo project 
• There could be structural issues in the XML file after translations were added
• Encoding problems might have occurred with the XML file after translations were added
• Other potential causes...

The information provided is not sufficient to provide a definitive answer. It would be beneficial to create a support case at https://gateway.sdl.com/ There could be a variety of reasons causing the issue.

• The XML files were exported from another Passolo project 
• There could be structural issues in the XML file after translations were added
• Encoding problems might have occurred with the XML file after translations were added
• Other potential causes...