Hi -
The Smoke Particle system was not really built for use in a mobile game and has always had issues when in viewed in mobile. They are appearing that way because Lit particles do not function correctly in mobile. If you go into the base Material for the Smoke, M_smoke_subUV, and change the Material’s Lighting Model to Unlit and reconnect what was in Base color to Emissive, the particle system will work just fine in mobile.
Thank You
Eric Ketchum