The character properties applied on the last paragraph symbol for a paragraph in a list (e.g. font family), are exported to HTML for the whole paragraph which is in the list.
As a notable side effect, when such HTML is imported, the default font size for a paragraph in a default bullet list changes to Symbol.
: The bug is introduced in 2016_2_613.
: Change the styles to export as inline properties:
htmlProvider.ExportSettings.StylesExportMode = StylesExportMode.Inline;
but be aware that this may cause issues as described in the related RichTextBox: Character properties of the paragraph symbol are not exported to HTML when StyleExportMode is Inline