Yes, this is an issue with how HTML handles whitespace vs. how vBulletin's parser handles whitespace.
The whitespace issue (for links anyway) will be obsolete in 3.x, because it would reduce to the same URL. VaultWiki no longer finds articles based on title, but instead on the processed URL. This prevents situations like having two articles called "Stop & Go" and "Stop and Go", both would go to the same article without needing the redirect. It also makes sure things like "Stop and Go" and "Stop & Go" go to the same place.