Called 'Dutch Rolling'.
Don't know why the Dutch are blamed.
Often a pilot may know when to put in a touch of rudder to disrupt the oscillation for a while but it is a natural effect of the existing stabilities and the interactions between yaw and roll. A small disturbence will set it all going again.
A simple fix may be to increase the sensitivity of the yaw damper providing this did not have detracting effects elsewhere.