Piko would ask you what power supply and throttle you are using. Soundtraxx decoders need clean power, so too much voltage (over 22V/24V max) would be an issue as well as brand of power. NMRA standards say 24V, but nearly all 24V power systems send more than that to the track when waves are calculated, so you likely want 22V or a little less. Piko might actually be the only manufacturer that actually follows NMRA exactly, so most folks blame them - even though "NMRA standards" are supposed to be standard.
My Piko mogul would flash lights when power was too high. Once I used a "NMRA standard" transformer it was all good. I think Piko uses a 20V/6A power supply on their digital system.