I have had similar experience recently.
I bought mine in August - rode it home 120 miles with 0 psi, stock springs - scary on turns....
bumped up to 12 psi - much better...
swapped out stock springs with progressives (0 psi) - way better - a little bouncy @ 35 mph on a hot summer day...
replaced existing fluid with Amsoil synthetic ATF - reduced bounce @ 35 mph 80% gone, still some bounce on a hot summer day...
then it dawned on me! waited for next hot summer day, rode a few miles, till I felt some bounce @ 35 mph - stopped and let out the built up pressure - THATS IT
nice ride, no dive, good absorption on bumps, no bounce issue, good 2up handling - haven't looked back...