Forum:How is editing information listed?

I have been accused of removing an unregistered users edit/post. The information that says I have is here > http://splintercell.wikia.com/index.php?title=Talk:Anna_Gr%C3%ADmsd%C3%B3ttir&diff=prev&oldid=16014

I did not edit line 8. I edited line 27.

How is it that someone else's edit has ended up on that contribution of 16014?
 * This could have happened in two ways:

This does happen on wikis, I've personally seen it more than a few times -- Random Time  17:31, July 12, 2010 (UTC)
 * 1) You had an edit conflict, and the software saved your edit withought bringing up the edit conflict box (sometimes happens).
 * 2) You accidentally edited an earlier revision (for example, you were looking at this revision and edited the page, meaning the IP's contibs were removed).