I have commented in the past on additions to the lede that add new material which isn't already in the main article. From MOS:LEAD (emphasis added):
- The lead serves both as an introduction to the article and as a summary of its most important aspects.
- The lead should contain no more than four paragraphs, must be carefully sourced as appropriate, and should be written in a clear, accessible style with a neutral point of view to invite a reading of the full article.
- The lead section should briefly summarize the most important points covered in an article in such a way that it can stand on its own as a concise version of the article. ...
- ... the reader will know that greater detail is saved for the body of the article.