I don’t think it’s a real bug, tho. Try pasting your markup into a plain text editor like Notepad or Textedit. With the font preference set to a proportional one like Arial or Helvetica, you should see the same problem. With it set to a monospace font like Consolas or Menlo, it should line up.
The variable size of the characters makes it hard to align things vertically unless they’re at a tab stop. In this case, a space is narrower than a dash; so the 2 spaces that start the second paragraph take less room than the dash and space that start the list item, which makes the text of the second paragraph starts a little farther to the left than that of the list item.
If you don’t mind using a monospace font, you could use a CSS snippet to set your Live preview font to one.