I translate sentences to earn coins but not all the coins I earn show up in the count. For example, I will have 14 coins left until I master the skill. Then I correctly translate a few sentences and go back and I still have 14 points left. Is this happening to anyone else?
When you submit the translation, the site shows you how many coins you earned and to what skills they go. Maybe you just did translations that don't refer to that specific skill. You can just test out of the skill (see the button on the top right when you are in the unit).