Yes I've seen the bit with the "disconnect" if you  break the handshake.

The only other thing I can think of is this ...

After you bring your morph into Poser and test it, and then decide that it needs more work ... keep the morph dialed in. See what happens if you export it as a POSED figure back into a new ZBrush document. This way, you have your previous work, and can pick it up from there.

Hopefully, the only thing that will be sent back into Poser will be the changes that you made in the second trip.

Worth a try.