asterisk users - Dec 2009 - sip show channels shows non-existent channels on 1.6.0.19 and 1.4.27.1 ?

I never do sip show channels but i tried it this morning to see if 
everything is working after upgrading 2 boxes to 1.6.0.19 and 1.4.27.1

Is it correct that Asterisk doesn't clean up sip channels anymore after 
using them ?

On one box i can see sip lines for every phone that was attempted to call, 
on the other box i see sip channels for 2 sip peers i register too. This 
is the output on the console:

1.4.27.1 :
pbx*CLI> sip show channels
Peer     User/ANR    Call ID      Seq (Tx/Rx)  Format Hold   Last Message
1.1.1.1  mysipname   576687fc4a8  00573/00000  0x0 (nothing)  No
10.0.0.0 221         774a1331284  00102/00000  0x0 (nothing)  No 
Init: NOTIFY
10.0.0.1 224         0359f0d23a4  00102/00000  0x0 (nothing)  No 
Init: NOTIFY

etc.

1.6.0.19 :
Peer             User/ANR    Call ID          Format           Hold 
Last Message
8.0.0.0     (None)      d34db33f-125982  0x0 (nothing)    No 
Rx: OPTIONS
8.0.0.0     (None)      d34db33f-125982  0x0 (nothing)    No 
Rx: OPTIONS
2 active SIP dialogs


Ip addressed modified (nuked) for the above examples

Is this normal?