Is this bug or feature? Review Status number under sub-decks wrong

There are some sub-decks under “PRELIMS-SYLLABUS…”

I reviewed one note in “2021-03-March”, and came back to the decks list. If you noted, as shown in the below image, All cards that is under the main deck “PRELIMS-SYLLABUS…” shows the “New” card status as 19, although I reviewed only one Card under “2021-03-March”.

Every other “New” card status should be “20” except “2021-03-March”, right?

To make it more clear, I reviewed just another card. Now, every deck shows “18” as New Cards left. It shouldn’t be all “20” except “2021-03-March”?

Sorry if this is a stupid question, I am new to Anki, and I was reading the Anki manual and organizing the decks using the “::” in Deck name to make it go as sub-decks.

If all these decks are separate, main decks, this issue vanishes, no problem. As every decks manages it’s own status, I think.

Thanks in advance for any reply,

It’s important to note that the blue number indicates the new cards that will be introduced today, not the total amount of new cards in the deck.

The new cards limit of the parent deck applies to all subdecks, that’s why the new card count is decreased on each one: Anki's not showing me all my cards! - Frequently Asked Questions