asterisk users - May 2009 - Bridge() and Goto() and dialplan contexts, oh my!

I may or may not be experiencing the behavior described in:
http://bugs.digium.com/view.php?id=14241

I'm using asterisk-1.6.0.6, Bridge(), and I'm having a hangup context
executed when the caller is still on the line. These channels are all
SIP.

===
I want a group of expert callers who can dial in to the system, stay
put, and let other learner callers come to them. In between the
learner callers, I want them to hear hold music. :

exten => 111,1,Goto(Expert_Gateway)
exten => 222,1,Goto(Learners)

[Expert_Gateway]

exten => s,1,Answer
exten => s,2,AGI(authenticate_and_register)
exten => s,3,MusicOnHold()
exten => s,4,Goto(Expert_Gateway,s,3)
exten => s,5,HangUp

exten => h,1,AGI(cleanup_registration)
exten => h,2,HangUp

[Learners]
exten => s,1,Answer
exten => s,2,AGI(find_channel_with_expert)
exten => s,3,Bridge(${EXPERT_CHANNEL})
exten => s,4,NoOp(${BRIDGERESULT})
exten => s,5,HangUp

exten => h,1,NoOp(${BRIDGERESULT})
exten => h,2,HangUp

Everything looks good at first. However, I think I'm misunderstanding
something fundamental about Bridge(). Everything works great for the
first Learner call, the learner gets bridged to the expert.
The bad news is that on the Expert side of the dialplan, the Hangup
side of the Expert_Gateway context gets executed during the Bridge()
to the Learners, including the AGI(cleanup_registration).

Is it expected that the Expert side gets hungup context executed if
they haven't really hungup?

When the learner hangs up the expert goes back to hold music, that is,
after the Bridge() exits, the Expert s context continues and properly
follows the Goto.

Should I file a new bug about this, or is this expected behavior? Am I
misunderstanding something fundamental about purpose of Bridge(), and
is there something else I should be using instead?