I'd try putting it in the Wishlist Forum first.

Since most plugins work fine, I'm guessing it is something these plugins are doing differently when saving/loading sounds.
Could be wrong, but a whole lot of synths seem to work fine. It may be something proprietary that the programmers haven't yet encountered.

If you feel it's a 'bug' in current PGMusic products, right now the Chat option at top of page appears 'online'.
Give them a shot. A good chat session can move things along quickly.
Make your sound your own!