The same issue is observed with heading styles.
The HtmlExportSettings property PropertiesToIgnore can't be used to control how the paragraph or character properties of a list will be exported. Steps to reproduce: Create a document with a list of different levels. Set fp.ExportSettings.PropertiesToIgnore["li"].Add("margin-left"); Export to HTML. Observed: The PropertiesToIgnore doesn't work for paragraph properties of a list.