My Synergy, purchased July this year, also had massive elevator flutter. Both elevators were snapped completely across the chord, and the flutter went on to snap both sides of the tailplane. Only the covering held it together long enough to land safely. I made a new tail and elevators from solid 1/2 inch balsa with holes cut out to lighten them but th holes are unecessary since even with a YS90 up front and 3 servos in the tail I am still adding lead to the tail.

All my pushrods were c/f tube epoxied over the steel rod and there is no slop at all in the linkage.

The elevators and tail supplied were totally inadequate for the job, the balsa was so thin that it was suitable for a free flight model. Both elevators snapped at the junction with the forward aerodynamic balance which is clearly the main stress point. I am not impressed by that on such an expensive model, the resulting flutter might have led to a crash causing a death in which case I would have pointed the finger of blame straight at ZN Line.

H