Stuck in a time loop, pls. advise!

For your perusal: timeloop - YouTube
It seems all LingQ’s I create in Cantonese get reset when I close the lesson. It feels like I’m stuck in a time loop. Did I exceed a quota or something? I don’t have such problems in other languages. IIRC this started after the January 5 web update. I can reproduce on a variety of browsers. Happens also on iOS/iPadOS although there it seems to get cached for some time and only resets a bit later.
Here is an example lesson: Login - LingQ

Thanks for reporting, we will look into the issue.