Well what I think what might happend is a reaction between nitrite and sulfide leading to the formation of elementary sulfur: H2S / HS- + NO2- --> S0 + N2 + H2O
The elementary sulfur would result in a yellow color but as far as I know elementary sulfur is insoluble in water and I don’t observe any precipitation.
Alternatively nitrite could be reduced to ammonium. The ammonium could then react with sulfide producing ammonium sulfide. H2S / HS- + NH4+ --> [NH4]2S
Ammonium sulfide is yellow and is extremely soluble in water. However, when nitrite is replaced by ammonium no yellow color occurs.