Why did ammonium chloride fumes turned pink in this synthesis? I was watching the synthesis of tetrasulfur tetranitride performed by Tom on his Youtube channel, Explosion &amp; fire. He followed the basic route: adding ammonia gas to sulfur chlorides ($\ce{SCl2}$ and $\ce{S2Cl2}$). At first, everything was going normal, purple-black precipitate on the flask with white $\ce{NH4Cl}$ fumes emitting as expected and white $\ce{HCl}$ fumes resulting from hydrolysis of sulfur chlorides. But suddenly a problem occurred. The fumes turned pink.  The following is a sequence in chronological order (snapshots from his videos; temperature of ppt. in brackets):


white $\ce{NH4Cl + HCl}$ fumes on top of precipitate ($\pu{T = 25 ^\circ C}$)

fumes turned pink ($\pu{T = 27-28 ^\circ C}$)

fumes entering the condenser from flask turning it red ($\pu{T = 35 ^\circ C}$)

fumes escaping the condenser ($\pu{T &gt; 35 ^\circ C}$)

condenser changed, $\ce{NH4Cl}$ pellets observed above it, fuming doesn't stop ($\pu{T &gt; 35 ^\circ C}$)


Eventually, after so much fuming and snowing, the end-product was achieved (when fumes turned golden brown, the original color of $\ce{S4N4}$). So, why did ammonium chloride fumes turned pink (when it was evolving)? Is it due to the compounds in the precipitate? If so, what species could have caused that color?
I did some research and found out that $\ce{S4N4}$ is thermochromic(changes color according to temperature). From britannica:

Tetrasulfur tetranitride forms thermochromic crystals, which are crystals that change colour with temperature. They are red at temperatures above 100 °C (210 °F), orange at 25 °C (80 °F), and colorless at −190 °C (−310 °F).

There is no mention of $\ce{S4N4}$ turning pink, so I proposed pink to be an intermediate color (orange -&gt; pink -&gt; red) and since it is a volatile compound, it was turning the fumes pink. But if the compound was pink, why did it later turn golden-brown, the original color of $\ce{S4N4}$? The precipitate was a purple-brown-black sludge, so it was definite not the end product. Thus my proposal contradicts.
prepchem says:

Tetrasulfur tetranitride is prepared by dissolving 1 volume of sulfur
dichloride in 8 or 10 volumes of carbon disulfide, cooling, and
passing in dry ammonia gas until the dark brown powdery
pre­cipitate which forms at first has dissolved and an
orange-yellow solution results which contains light-colored flocks of ammonium chloride.

Here, there is no mention of pink. What species could have caused fumes to turn pink in color?
I recommend to watch the synthesis in details on his second channel, Extraction &amp; Ire: Part 1 and Part 2
$\ce{NH3}$ and $\ce{SCl2}$ form $\ce{NH4Cl}$ which evolves as white fumes. $\ce{NH4Cl}$, when passed through $\ce{SCl2}$ (cherry-red liquid), gives the appearance of dense-pink fumes
$$\ce{\underset{(cherry red)}{6SCl2} + 16 NH3 -&gt; S4N4 +2S + \underset{(white)}{12NH4Cl}}$$
That is why the fumes of $\ce{NH4Cl}$ turned pink