check the underside of each nut pad, check for burrs or something, then check the
trem springs and, if needed, replace them with a new set.
be sure you lock the pads in the right way, you should see kind of ^^^ in a body-toward-headstock sight, and tighten them firmly.
also be sure the retainer-bar sits the lowest as possible and, if needed, take the truss-rod cover away.
hope this will help you, let us know.