Reverse DNS Sub-net folders being automatically created

I'm working on a joint project with another vendor and we've found a customer's DNS to be a little strange.  The forward lookup zones are all correct - but the reverse lookup zones are dynamically creating subfolders beneath the defined zone (see attached picture).

For example, the reverse lookup zone was created for 10.2.x.x.  Underneath that zone, folders for 10.2.1.x, 10.2.2.x, 10.2.3.x, etc are being created presumably by Windows.  The customer says they did nothing special when setting up the zones.

Everything seems to be working correctly so I'm of the mind-set that this isn't a problem but the other vendor remains convinced that it is.  I will agree it's not what I normally expected to see.  But then again, I haven't seen a lot of reverse DNS zones using Class B addressing schemes either.

Has anyone ever run across this?  And, if so, is it an indication that there's a problem somewhere with DNS setup?  The customer does maintain that all the subfolders have been created dynamically by DDNS.

Thanks.

DNSPTR.JPG