Problem Available Room

Hi, I have a problem with the available room.

I have a Standard Room with 10 room stock.
https://tinyurl.com/ygvs8se5

Then I created 1 manual reservation with ID #228 with 3 Standard Rooms.

But when I create again manual reservation same date with #228, I can create a manual reservation with 8 Standard Rooms.

Here’s the screenshot. https://tinyurl.com/yjdf43a2
You can see ID #229 have same date with #228

Also from the front-end, you can see that the rooms are still available.
https://tinyurl.com/yel5k9bz

I don’t understand, is this the bug? or just me confusing how to set up the plugin.

Thank you.