Then the problem is from you, in Infernal Cyclone, dummy.mdl with Trail Fx works perfectly
for more info:
if not (udg_KB3D_TrailFx == "") and not (udg_KB3D_Fx_Attach == "") then
call SaveEffectHandle(udg_KB3D_HA, 14, udg_KB3D_Counter, AddSpecialEffectTarget(udg_KB3D_TrailFx, udg_KB3D_Unit, udg_KB3D_Fx_Attach))
endif
This is how the Trail is created, and how it is destroyed:
if HaveSavedHandle(udg_KB3D_HA, 14, Loop) then
call DestroyEffect(LoadEffectHandle(udg_KB3D_HA, 14, Loop))
endif