Can't finsh level on Russisch 5

Whenever I try an finish the level _ Das Wetter auf der Erde_ (Level 16) on the Russisch 5 course, I get an error message. This means I can’t finish the course or the level. It’s not a huge problem, but it’s still a bug. Has anyone else got this? Is it fixable?
Additional info; the level is described as 96% complete (27/28 words) and the mobile app tells me that I have one word left to learn. However I have learnt all the words listed within the level. I think this is the source of the issue.
Sorry if this post is in the wrong place, it is my first foray into the community.
Thanks in advance!

It has seemed to resolve itself. Thanks guys.
By the way, there are a few typos in the Russisch 1-7 courses, but these will probably also resolve themselves.