Private lessons can be read by other members

Yesterday I wrote a lesson for my new collection “Un italiano a Sofia” and saved it at least twice while I was writing it. Then I didn’t share it both because I wanted to be able to change it again and because I still hadn’t recorded it.
However, Jolanda was able to read it by opening the previous, shared, lesson and by clicking on “go to next lesson”. I think members shouldn’t be allowed to read unshared lessons. Ok, this lesson was meant to be published as soon as I’d have the recording, but it could have be a private lesson I didn’t want anyone to read or I couldn’t share.
Any help and explanation are welcome,

As far as I know is this a known error. Someone explained this problem long time ago.

A tempory solution: Put this lesson in another collection (named ‘private’) as long as it is private. When you finished it you could put it into the correct collection.

Danke, Vera. I don’t think I can move this lesson any more, because it’s being used by other members, but next time I will do as you suggested.

You can still change the collection. This prevent that more users take this lesson.

Well, I have shared that lesson now. So, I’ll take your advice into account next time.