Do I need to do something special with Server 2008 R2 with DNS....?

Hi, do I need to do something special with Server 2008 R2 when it comes to DNS scavenging & aging?  I have replaced my main DC from Server 2003 to Server 2008 R2.  The old Server 2003 had scavenging & aging setup correctly.  When I replaced it with a new hardware server running Server 2008 R2, I verified that it was setup correctly for DNS Scavenging & Aging.

Recently, I was going thru the DNS records when I discovered several DNS records (A), probably half dozen or so that were duplicates, meaning same IP with different PC names.

So, I am not sure what is going on or what I have missed with DNS Scavenging & Aging on the 2008 R2 box.  This server has been in place for a year now and I am just now seeing this.  So, not sure if it is because of my busy techs promoting & demoting PC's to/from the domain & it just takes time for the scavenging to catch up, which is what I read or if something else is going on.

Any ideas, suggestions or things to check/verify that DNS Scavenging & Aging is working correctly on the Server 2008 R2 box, will be greatly appreciated.

Thanks in advance.