Hi Claudio, I appreciate your quick return.
The warning seems to be the same as it shows in the CRAN webpage, so it looks like the error is not related to the data. Nonetheless, I attached to this email a very short dataset (subset of mine) and the simple code I tried to use. I did not make much effort on customizing the code through the package, but rather tried to produce the plot directly through ggplot, which now returned a similar graphic (I also attached it to the code).
Let me know if you have any news, and thanks in advance!