Missing nucleotides in entropy output .tsv file

Hi, when I select for Dengue the whole genome, and export the genome diversity data (entropy) to a .tsv file, I have missing nucleotides in the output file. In my TSV file I only have 7947 rows for the genome that has 10649 nucleotides. I read the Missing sequence data (gaps, indels, ambiguity) — Nextstrain documentation but I don’t see a clear description for this case.