Sgt_Kickaxe - 5:32 am on Dec 12, 2012 (gmt 0)
I'm not sure what the OP meant by "upcoming links" but I'm going to assume incoming.
Scraper bots are the main cause of these types of googlebot queries imo, they malform the link back to your site (if they link at all) and CMS systems like wordpress flub the 404 or 301. I see Googlebot requests for urls ending in the above more than I'd like in wordpress especially, but in all CMS systems.
rel=canonical tags tell Google which version you want indexed, it's a start.