IMAP email attachments are corrupted.How to set the encoding?

Hello,

I'm reading attachments from IMAP using the following code. My issue is the file content is getting corrupted. As you may notice, I've used the encoding attribute almost every where possible. But the characters are getting corrupted. E.g, my input file has the content as "bátu" which becomes "bátu". What should I do to avoid it.

If I read the same file using a file connector, there is no corruption.

 <imaps:inbound-endpoint host="XXX"
             port="993" user="XXX" password="XXX"
             connector-ref="IMAP" responseTimeout="10000" doc:name="IMAP" />
 <expression-transformer doc:name="Put Attachments to Payload"
             encoding="utf-8">
             <return-argument evaluator="attachments-list"
                 expression="*" />
         </expression-transformer>

Followed by...

 <collection-splitter doc:name="Collection Splitter" />
                 <message-properties-transformer
                     doc:name="Message Properties">
                     <add-message-property key="fileName"
                         value="#[groovy:payload.name]" />
                 </message-properties-transformer>


 

 
     <object-to-string-transformer encoding="utf-8" mimeType="application/csv" doc:name="Object 
         to String" />
 <logger message="Payload: #[payload]" level="INFO" doc:name="Logger" />