diff --git a/app/models/app.rb b/app/models/app.rb
index 5fa412b..8e80221 100644
--- a/app/models/app.rb
+++ b/app/models/app.rb
@@ -81,7 +81,8 @@ class App
   end
 
   def find_or_create_err!(attrs)
-    Err.where(attrs).first || problems.create!.errs.create!(attrs)
+    Err.any_in(:problem_id => problems.map { |a| a.id }).
+        where(attrs).first || problems.create!.errs.create!(attrs)
   end
 
   # Mongoid Bug: find(id) on association proxies returns an Enumerator
--
libgit2 0.21.2