FIX: filter conditionally excluded fields from wizard submission

lib/custom_wizard/wizard.rb

@@ -243,10 +243,16 @@ class CustomWizard::Wizard
     return nil unless save_submissions
 
     submissions.pop(1) if unfinished?
+    submission = filter_conditional_fields(submission)
     submissions.push(submission)
     set_submissions(submissions)
   end
 
+  def filter_conditional_fields(submission)
+    included_fields = steps.map { |s| s.fields.map { |f| f.id } }.flatten
+    submission.select { |key, _| included_fields.include?(key) }
+  end
+
   def final_cleanup!
     if id == user.custom_fields['redirect_to_wizard']
       user.custom_fields.delete('redirect_to_wizard')