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A weird little strengthened skill bug?

I was refreshing some skills tonight, and then completed a new lesson, when I realized a weird pattern. Each time I actually strengthened or acquired a skill, two additional skills would show up, completely unrelated!

Here is the last example that made me notice it: Alt text

I didn't even strengthen Abstract Objects 4.. I was doing a lesson.. and it had nothing to do with the bonus lessons. They showed up about 4 times just in the past hour, all with the same amount of progress bars. Has anyone else had this little odd bug?

March 20, 2014



Thanks for reporting, this should be fixed now! Do let us know if the problem should persist.


It still happens. I thought this was normal, as once more than 5 skills were strengthened at the same time.

To me it makes perfect sense since the words were included in the previous skills, and it kind of works a bit like the summary of learnt words that appeared in the good old days before the redesign. :)


So what is the consensus:

  • Is this a bug or a feature?
  • Is it also normal when a review session doesn't strengthen a skill, e.g. when there aren't enough words to strengthen the overall skill?


It's okay for a lesson or practice session to strengthen more than one skill, this post actually referred to a particular issue where bonus skills would show up as strengthened whenever you practiced. :)


Thanks for the information. I've also seen several confused users indicating that sometimes no skills are strengthened after a practice session, it has also happened to me. Mostly during timed practice. So what about the second question, is it normal or could it be indicative of a bug?


That depends on the overall word strength for that skill, but in general, it's not the case that every session has to strengthen a skill.



You might get better responses if you move your post to troubleshooting.

To do that click “edit” below your post, and than scroll up to the top to choose this forum in the drop down menu. Then save!


Oh, how embarrassing, I haven't noticed this option. Thank you :)


You can add picture by typing ![Alt text] (Your link here

Alt text


Thanks! I couldn't figure out what format to use.


I got the same thing, and I think it is actually a feature, although it is a bit obscure.

I looked in the duolingo web-cookie, and I can see that Duolingo is running an experiment called: skill_practice_dependency_experiment, and I believe this is what causes this.

My best guess is that it works like this: If you strengthen a skill, and any of the earlier skills (the skills that the current skill "depends" on) in the tree have less than full strength, then they will show up after the practice session as a reminder.

I do however agree that it is less than obvious why those extra skills are being shown at the end of a practice session!

[EDIT] I missed the part about that you did not even strengthen Abstract Objects 4. Indeed there seems to be bug when you are not strengthening anything, I have just tested this, and I can confirm that this happens for me too! When I make a timed practice and only answer one (non-christmas related) question, then it will always tell me that I have strengthened Christmas.


Thanks for those details! We're investigating and will fix this asap.


have sent my screenshots and raw html (firefox Version 28)
via ticket #183751


Thank you! We are looking into it. Appreciate the screenshots :)


I have the same issue! The bonus lessons seem particularly fond of being mystically strengthened.

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