When I hibernate a card in lesson mode, this card is not replaced by a new card right away to achieve the desired batch size. Instead, I have to finish or cancel the current lesson session first, before a new card is added to the batch. So for example, if I have three daily lessons and hibernate a card in lesson mode (because I know the card content by heart already), I have to finish the two remaining cards in quiz mode first, and then I have to start another lesson session to study the new card replacing the hibernated one.
This is a bit annoying for me, because I’m doing the Japanese 10k deck, but I already know a lot of vocabulary. So when I do new lessons, I always hibernate cards I already know right away. Because the batch is not “refilled” during a lesson session, I often have to do several sessions where I only have one card in the batch which I already know and hibernate, until I get to a session with a card I don’t already know. It would be great if hibernated cards could get replaced during the lesson sessions, not only inbetween.
I hope I could explain the issue well enough ^.^’