On LingQ iPhone app, the playlist doesn't work well

When I add lessons to the playlist, lessons are in the playlist, as you know.

But, there are no lessons in the playlist when I use other apps and return to the LingQ app.

Please address this issue.

Hi Hiroshi,
I am sorry to hear that you’re having troubles with creating a playlists. All playlists can dissapear after you reinstall the app, but not if you just reopen it.
Can you please try to reinstall the app and try after that? That should solve your issue. Thanks.