diff --git a/app/controllers/projects_controller.rb b/app/controllers/projects_controller.rb
index 6ea9b2cf27d2151550002d6df5a13059d6246b21..7401b28ea1d5610d60033468156641acaffe57b4 100644
--- a/app/controllers/projects_controller.rb
+++ b/app/controllers/projects_controller.rb
@@ -217,6 +217,6 @@ class ProjectsController < ApplicationController
   end
 
   def sorted(users)
-    users.uniq.compact.sort_by(&:username).map { |user| { username: user.username, name: user.name } }
+    users.uniq.to_a.compact.sort_by(&:username).map { |user| { username: user.username, name: user.name } }
   end
 end