I encountered similar problem recently. The fix is to set the display property of the li items in the ordered list to list-item, and not display block, and ensure that the display property of ol is not list-item. i.e
li { display: list-item;}
With this, the html parser sees all li as the list item and assign the appropriate value to it, and sees the ol, as an inline-block or block element based on your settings, and doesn't try to assign any count value to it.