Tank vs Gravity - Sopuli

https://www.instagram.com/reel/DTnfDFpiG_3/ [https://www.instagram.com/reel/DTnfDFpiG_3/]

Is it normal for tanks to have such black smoke? Seems like a tactical disadvantage, while also bad for the troops in the short term (troops that cannot breath well won’t be doing much well.)
Normal being relative? It’s a diesel engine that will “roll coal” if it’s fed too much fuel. Occasionally that can be normal and used tactically to create a smoke screen. However this particular one I’m chalking to beat up engine issues - clogged air filters or failing fuel injectors.
It could also just be a cold engine.