I've noticed that I am getting Event ID 4515 events in my logs and using ADSIedit have determined that I have duplicate entries in my DNS for my domains.
In the article found here it is recommended that you pick either ForestDNSzone or DomainDNSzone as the main replication location and delete the entries in the other.
I am running a 2008R2 forest with all 2008R2 DCs with one root domain and one child. One thing that I cannot determine is which is the better choice: Forest zone or Domain zone? Based on my reading it appears the DomainDNSZone is the better spot but I want to know why.