New AD site subnet

we have two site and subnet is: 

10.1.0.0/16 Site A

10.2.0.0/16 Site B

I'm on 10.2.1.100 client , nltest query

nltest /dsgetdc:hongkong.local

sometime return show correct Site B name , sometime return show Site A name.

Very confuse , does I split the site success?

Thanks.