diff --git a/app/controllers/exercises_controller.rb b/app/controllers/exercises_controller.rb
index 75451eb3..cb6e9c9d 100644
--- a/app/controllers/exercises_controller.rb
+++ b/app/controllers/exercises_controller.rb
@@ -247,23 +247,34 @@ class ExercisesController < ApplicationController
   end
 
   def redirect_after_submit
-    Rails.logger.debug('Score ' + @submission.normalized_score.to_s)
+    Rails.logger.debug('Redirecting user with score:s ' + @submission.normalized_score.to_s)
     if @submission.normalized_score == 1.0
-      # if user has an own rfc, redirect to it and message him to clean up and accept the answer.
+      # if user is external and has an own rfc, redirect to it and message him to clean up and accept the answer. (we need to check that the user is external,
+      # otherwise an internal user could be shown a false rfc here, since current_user.id is polymorphic, but only makes sense for external users when used with rfcs.)
+      if current_user.respond_to? :external_id
+        if rfc = RequestForComment.unsolved.where(exercise_id: @submission.exercise, user_id: current_user.id).first
+          # set a message that informs the user that his own RFC should be closed.
+          flash[:notice] = I18n.t('exercises.submit.full_score_redirect_to_own_rfc')
+          flash.keep(:notice)
 
-      # else: show open rfc for same exercise
-      if rfc = RequestForComment.unsolved.where(exercise_id: @submission.exercise).order("RANDOM()").first
+          respond_to do |format|
+            format.html { redirect_to(rfc) }
+            format.json { render(json: {redirect: url_for(rfc)}) }
+          end
+          return
 
-        # set a message that informs the user that his score was perfect and help in RFC is greatly appreciated.
-        flash[:notice] = I18n.t('exercises.submit.full_score_redirect_to_rfc')
-        flash.keep(:notice)
+        # else: show open rfc for same exercise if available
+        elsif rfc = RequestForComment.unsolved.where(exercise_id: @submission.exercise).order("RANDOM()").first
+          # set a message that informs the user that his score was perfect and help in RFC is greatly appreciated.
+          flash[:notice] = I18n.t('exercises.submit.full_score_redirect_to_rfc')
+          flash.keep(:notice)
 
-        respond_to do |format|
-          format.html { redirect_to(rfc) }
-          format.json { render(json: {redirect: url_for(rfc)}) }
+          respond_to do |format|
+            format.html { redirect_to(rfc) }
+            format.json { render(json: {redirect: url_for(rfc)}) }
+          end
+          return
         end
-
-        return
       end
     end
     redirect_to_lti_return_path
diff --git a/app/controllers/request_for_comments_controller.rb b/app/controllers/request_for_comments_controller.rb
index 37d8bef9..f9e7137e 100644
--- a/app/controllers/request_for_comments_controller.rb
+++ b/app/controllers/request_for_comments_controller.rb
@@ -82,6 +82,7 @@ class RequestForCommentsController < ApplicationController
 
     # Never trust parameters from the scary internet, only allow the white list through.
     def request_for_comment_params
+      # we are using the current_user.id here, since internal users are not able to create comments. The external_user.id is a primary key and does not require the consumer_id to be unique.
       params.require(:request_for_comment).permit(:exercise_id, :file_id, :question, :requested_at, :solved, :submission_id).merge(user_id: current_user.id, user_type: current_user.class.name)
     end
 end
diff --git a/config/locales/de.yml b/config/locales/de.yml
index a57b2c04..b34d6a7a 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -274,6 +274,7 @@ de:
     submit:
       failure: Beim Übermitteln Ihrer Punktzahl ist ein Fehler aufgetreten. Bitte versuchen Sie es später erneut.
       full_score_redirect_to_rfc: Herzlichen Glückwunsch! Sie haben die maximale Punktzahl für diese Aufgabe an den Kurs übertragen. Ein anderer Teilnehmer hat eine Frage zu der von Ihnen gelösten Aufgabe. Er würde sich sicherlich sehr über ihre Hilfe und Kommentare freuen.
+      full_score_redirect_to_own_rfc: Herzlichen Glückwunsch! Sie haben die maximale Punktzahl für diese Aufgabe an den Kurs übertragen. Ihre Frage ist damit wahrscheinlich gelöst? Falls ja, fügen Sie doch den entscheidenden Kniff als Antwort hinzu und markieren die Frage als gelöst, bevor sie das Fenster schließen.
     external_users:
       statistics:
         no_data_available: Keine Daten verfügbar.
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 691dfe72..e1663e5d 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -274,6 +274,7 @@ en:
     submit:
       failure: An error occured while transmitting your score. Please try again later.
       full_score_redirect_to_rfc: Congratulations! You achieved and submitted the highest possible score for this exercise. Another participant has a question concerning the exercise you just solved. Your help and comments will be greatly appreciated!
+      full_score_redirect_to_own_rfc: Congratulations! You achieved and submitted the highest possible score for this exercise. Your question concerning the exercise is solved? If so, please share the essential insight with your fellows and mark the question as solved, before you close this window!
     external_users:
       statistics:
         no_data_available: No data available.