Some words in skills are more frequent than other
When practicing unfinished skill some words migrate from one to another. I found that when you finish two lessons from one skill some words from first lecture go to second lecture. When you finish third skill the same words from 2nd lesson migrate to third and so on and so forth until you finish entire skill.
But most irritating is another feature that due this bug (or another bug) some words do not appear at all.
To be more specific: I've finished 8th lesson from Inf. 2. Now it looks like:
créer, découvrir, compter, tuer, vivre, chercher, demande
Originally it looked like:
créer, découvrir, compter, tuer, gagner, recevoir, aider
You see that three last words (vivre, chercher, demander) migrate to each new lesson. And I've discovered that I've never seen a sentence with a word "créer".
I've tried to report this bug several times.