DNS Configuration

I have a Forest A with child domains B and C.
DNS is configured with A.com and within A.com the domain B and C are listed. Server b1 is in the b.a.com domain. I have a DNS host(A) entry for b1 in A.com and I have a host(A) entry for b1 in b.a.com. From the forest root A.com DC I ping b1 – and I get a ping response of b1.a.com – the problem is this server (b1) is part of the b.a.com domain – should the ping not be b1.b.a.com?