I deleted an imported lesson on the browser, but it still remains in the course on Android.
I had opened the two episodes of Radar ep. 3. on Android. I then deleted these two lessons on the browser.
When I went back to Android, these two lessons still appeared in the course. Even after I refreshed it and waited a day, even though they were deleted, they remained in the course.
I thought this might be because they are still in the cache. So I uninstalled the LingQ app and reinstalled it and this removed the two lessons from the course.
As you can see, deleting a lesson on the browser does not remove the lesson from Android if it has already been opened (and cached).
This is similar to a bug I reported the other week, where replacing the audio file on the browser does not update the audio file on Android, if it has already been cached.