XLS Formatter error :the input file already contains formatting styles only in the last iteration

I have been trying to use the XLS formatter to do some modifications in each excel sheets. But this works for all the iteration just before the last one. Only for the last one I am recieving the error:

Execute failed: The input file already contains formatting styles. This is currently unsupportet in our extension beyond a degree that KNIME’s XLS Writer and sheet Appender nodes would utilize.

As mention as result I see all the changes until the last sheet where the changes are not there because its not completed (the iteration)