diff --git a/lib/ripple/conflict/resolver.rb b/lib/ripple/conflict/resolver.rb
index b19f0485..1685b976 100644
--- a/lib/ripple/conflict/resolver.rb
+++ b/lib/ripple/conflict/resolver.rb
@@ -11,6 +11,7 @@ class Resolver
 
       def self.to_proc
         @to_proc ||= lambda do |robject|
+          return nil unless robject.data.nil? or robject.content_type=='application/json'
           possible_model_classes = robject.siblings.map { |s| s.data && s.data['_type'] }.compact.uniq
           return nil unless possible_model_classes.size == 1