I wonder if you are thinking "monster" when it's really a "mouse"? "Shadows" (i.e., "symptoms") can be deceiving.
If you haven't done so already, I would look carefully at clutch cable adjustments. Remember there are two places (three, really) to adjust the cable action on this scooter. There's the handlebar clutch lever, the cable end under the engine, and then the actuator lever under the engine (bell housing).
During maintenance this past winter I replaced the clutch cable on my '98 EV. I continue to have to adjust the handlebar clutch cable adjustment from time-to-time to "cure" 1st-to-neutral-to-2nd gear shifting problems when I am stopped. Changing the cable caused the transmission to behave totally different when trying to find neutral. It also made it difficult to shift from neutral to 1st at times.
Eventually all of the "stretch" in the cable will work itself out. Then the transmission will shift into neutral the same way time-after-time until I change the cable again.
So, personally, I'd think "mouse" and work at getting the clutch cable adjusted "just right." If that doesn't do it, I'd get another Guzzi person to take a look at it. I wouldn't entertain the thought of "monster" until the clutch cable was known to be a "non-issue."
Edit: There is a Guzzi model that was prone to break it's shift lever return spring (IIRC). But I don't remember which scooter it is - someone will chime in and correct me/fill in the information.
Good luck!
Bill