[p4] Problem with integrates

[Matt Roberts]

We have 2 branches setup as follows:

//branches/old/...
//branches/new/...

And a branchspec defining the mapping from //branches/old/... to
//branches/new/...

There is a change in //branches/old/... that affects only one file.  Now
we want to merge that change over to //branches/new/...

Normally, we would do the following:
p4 integrate -b branchspec @12345, at 12345

However, in this particular situation, we get the error that there are
no such files:
@12345, at 12345 - no such file(s)

But, I know the file in this changelist exists in both branches and is
mapped by the branchspec.  So I try this command:
p4 integrate -b branchspec //branches/old/path/to/file.txt at 12345, at 12345

That works!  So, I start pulling back the file spec in that command
until I find that this will not work:
p4 integrate -b branchspec //branches/old/path/... at 12345, at 12345

but this will:
p4 integrate -b branchspec //branches/old/path/t*/... at 12345, at 12345

Now, the branchspec is rather large since there was a lot of code re-org
in the move to the new branch. There are also exceptions in the branch
spec relating to some stuff in old that we didn't want in new.  I have
double and triple checked that none of the exceptions would affect the
file in question.  In fact, I would think that the integrate would not
work when specifying the full path if there was an exception that
affected this file.

Has anyone seen this behavior before?  What am I missing?

Thanks,
Matt