LingQ's of the day - there is a little problem

I began to look in the LingQs of day. Congratulations, very good work!
But my problem there is, I cannot change anything. My correction is done correctly, it is saved and to see for me if I look again, but it is not to see on the card.
Yesterday, I did this, too, and it worked sometimes and sometimes not. Is there a problem or am I doing anything wrong?

After some hours, I tried again and now it is working.