I know this is an old post but we have had the same issue with a new (2013) Samsung refrigerator top and freezer botton and this has happened to us twice...we think we know what caused the problem and how to avoid it in the future!
When changing the water filter unplug and drain any water from the backside of the refrigerator BEFORE you loosen or take out the water filter from the refrigerator. If you don't do this the water filter leaks water all over the refrigerator in places you will find hard to get to and create a foul smell. This has happened to us both times we changed the filter (the second time we weren't at home and our son without knowing changed the filter while we were out causing the smell AGAIN)! Hope this helps!
Dori
July 2014