definitely sounds like an encoding mismatch. If the HTML is not specifying the correct encoding you can call the following.
HTML2PDF.WebPageSettings.SetDefaultEncoding.
and pass this setting object into each of your HTML2PDF.InsertFromUrl calls.
From our documentation...
@note available encodings are Apple Roman, Big5, Big5-HKSCS,
* CP949, EUC-JP, EUC-KR, GB18030-0, IBM 850,
* IBM 866, IBM 874, ISO 2022-JP, ISO 8859-1 to 10, ISO 8859-13 to 16,
* Iscii-Bng, Dev, Gjr, Knd, Mlm, Ori, Pnj, Tlg, Tml, JIS X 0201, JIS X 0208,
* KOI8-R, KOI8-U, MuleLao-1, ROMAN8, Shift-JIS, TIS-620, TSCII,
* UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32, UTF-32BE, UTF-32LE,
* Windows-1250 to 1258, WINSAMI2.