I don't know if this is the same issue as the Unusual Enemy Spawn because this one didn't involve fast-travel like the other thread http://www.gamesas.com/topic/1354617-massive-spawn-inside-whiterun/.

We were walking to Markarth from Solitude when we came across some draugr walking on the road. They weren't hostile and when mousing over them, nothing appeared. One went a different way, two crossed a river and they all ended up walking together again. I took some shots then. Has anyone seen this? Is it a radiant thing maybe? G, if you'd like the savefile, just let me know, I've set it aside.

http://i1181.photobucket.com/albums/x438/Kicenna/Skyrim/TESV2012-03-0519-47-55-51.jpg
http://i1181.photobucket.com/albums/x438/Kicenna/Skyrim/TESV2012-03-0519-49-30-07.jpg
http://i1181.photobucket.com/albums/x438/Kicenna/Skyrim/TESV2012-03-0519-51-16-60.jpg