diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 8a4f8f6d8af1a239b6b079b61fd4d0fd604ff1c5..b302879fb6499acd2554d97bb57e602f1e1f8fc6 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -214,7 +214,7 @@ module ApplicationHelper
 
   # Truncates and returns the string as a single line
   def truncate_single_line(string, *args)
-    truncate(string, *args).gsub(%r{[\r\n]+}m, ' ')
+    truncate(string.to_s, *args).gsub(%r{[\r\n]+}m, ' ')
   end
 
   def html_hours(text)