Special characters getting removed with clean function in documents

Hi , I am facing an issue in pdf generation. that sometimes  frech and spanish letters getting eliminated from the document generated , letters like à, é. ó. I am using clean fucntion before passing the sentences to do document template.  If I don't use clean the generated document dont even getting saved in the process output even for english templates. Below is smart services I use to get the pdf generated. 

This is how it appear in the grid 

This is how it looks when printed,

Is there any way to fix this.

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