Soft setting on hard springs will accentuate short travel bounce / rebound - not very technical speak so maybe someone here will explain it better. The spring finds it easier to move - but stiff ones don't move a lot... so you get a kind of short skip on the lightest of bumps.

These things can take a fair bit of setting up so I hand mine over to some pro mates to sort for me... but it does sound like you have springs that are too hard for your needs I'm afraid.