[Svnmerge] Why is revision is "initialized" in some child branches and not others

[Ring_Nolan at emc.com]

All,

We're using: 

svnmerge r29854
Subversion v1.4.4

I'm having trouble understanding why some child branches are seeing a
particular revision of the parent as "initialized" while others aren't.

Our situation:
                                                 
     group dev branch1 ---------------|--(initialized for merging to
trunk @ rev 8899)       
                                      |
trunk
--------------------------------|r8899----------------|-----------------
------------
                                                            |
     group dev branch2 -------------------------------------|r8913
(merge from trunk -> group dev branch2 @8913 - svnmerge-integrated
property includes 
                                                                    info
on group dev branch1 for the first time as well as a ton of code new to 
 
this branch)

          child branch2A ---------------------------------------
(created @ rev 7707, initialized for merging @ 9072 - all code from

                                                                  rev
8913 from parent merges fine) 
          child branch2B ---------------------------------------
(created @ rev 7742, initialized for merging @ 8428 - rev 8913 from 
                                                                  parent
seen as "initialized" and skipped)
          child branch2C ---------------------------------------
(created @ rev 7704, initialized for merging @ 8080 - rev 8913 from 
 
parent seen as "initialized" and skipped)

I have a feeling this has something to do with the change to the
svnmerge-integrated property on group branch2 with the merge from the
trunk at rev 8913.   But I can't explain the details to myself (or
anyone else :-) )  Why are the branches initialized for merging to group
dev branch2 *after* rev 8913 on the parent behaving differently from
those initialized before 8913.

What am I missing or not understanding?

Thanks for slogging through this - and more thanks for any
insights/pointers/suggestions.

Nolan