Are you referring to what you see in the editor? Or are you seeing this in the output?
If it's the editor, that usually doesn't show up in the output. But there is something I'd advise. It sounds as though you selected text, then made the selected text a bookmark. I never advise working that way as you paint yourself into a corner if you ever need to change the bookmark's location! Instead, I recommend inserting the cursor just before the text and insert a bookmark that way. You then end up with a little flag icon that may be easily clicked and dragged to a new location on the page if you need to.