[A6] Strangeness with mix mode and portamento

[Denizen]

Hi Andromedans,

Even though I've had it for about a year, I've been playing with my A6 a
lot more lately now that I'm using it extensively in its first
production... the more I learn about it the more impressive and powerful
it becomes.  Anyway, the most recent confusing thing it's doing is
actually kinda cool, but I can't figure it out:

Okay, there is a patch of mine that behaves differently in mix mode than
in program mode.  I even re-saved it to be sure.  This leads me to believe
that what's causing it has something to do with the mix patch, but I'm
unaware of anywhere to modify a patch's portamento behavior that's
associated with a mix (and that overrides portamento config in the
program).

What's more, is that I wouldn't even know how to program what it's doing
in mix mode (which sounds really cool when you play it right):

Portamento is only applied upon _release_ of a key... it sliiides up to
the older voice.  When you play legato, it instantly snaps to the new key,
but then portamentos back to the previous one.

What do you suppose is happening?

-Denizen