NHF – new heroes for Heroes V 3.1.

The effect is disabled only because the NHF_Kiina_frendly_F function is called only if the hero is Kiina (to avoid breaking the system); otherwise, the effect would not be disabled.
StopVisualEffects does not raise an error if there are no effects, so a check is not necessary.

Effects do not need to be disabled while the mob exists.

function NHF_RemoveMobEffects(hero, mob)
	while IsObjectExists(hero) and IsObjectExists(mob) do
		sleep()
	end
	if not IsObjectExists(mob) then
		StopVisualEffects(mob .. "_Effect_Tag")
	end
end

function NHF_Touch_mobs_F(hero,mob)
	-- ... --
	if mob > "NHF" and mob < "NHG"  then
		startThread(NHF_RemoveMobEffects, hero, mob)
	end
	-- ... --
end