diff --git a/app/controllers/remote_evaluation_controller.rb b/app/controllers/remote_evaluation_controller.rb
index d6cdac13c..1c4967909 100644
--- a/app/controllers/remote_evaluation_controller.rb
+++ b/app/controllers/remote_evaluation_controller.rb
@@ -78,9 +78,11 @@ def create_and_score_submission(cause)
     end
   rescue Runner::Error::RunnerInUse => e
     Rails.logger.debug { "Scoring a submission failed because the runner was already in use: #{e.message}" }
+    @submission = nil
     {message: I18n.t('exercises.editor.runner_in_use'), status: 409}
   rescue Runner::Error => e
     Rails.logger.debug { "Runner error while scoring submission #{@submission.id}: #{e.message}" }
+    @submission = nil
     {message: I18n.t('exercises.editor.depleted'), status: 503}
   end