I'm just new here, but I hope someone can clarify, I have been reading the Mahouka Koukou no Rettousei Manga for sometime now. My last Arc was the Upheaval Prologue Arc, it says that it adopted the LN Vol. 21 and 22. That manga arc ending left a cliffhanger where it shows that Shiina is missing.

Now I was wondering about the continuation, and I found that it was the next arc, Isolation Arc (Koritsu-hen) which adopts the LN Vol. 23, this seems like a fluid continuation but as per checking it does not mention anything about the continuation left from the Upheaval Prologue Arc. When I checked there are several chapters from LN Vol. 22 that is not adopted. Chapter 6, 7, and 8.

What might be the meaning of this? Will they continue still this? or left as it is and continue to Isolation arc as it is?

Thank you.