Someone care to genuinely explain to me the physics behind Bangalore smoke?

It's been pretty sketchy ever since that change when they made the Switch port.  They reported fixing it, but Bangalore smoke and Caustic gas clearly do not consistently function quite the way they are supposed to.  What I have noticed is that lighting (specifically, the direction of) has a strong effect on visibility.  If you're on the right side of the smoke, you can see pretty well.  I find Caustic's case to be worse, because the highlighted vision one is supposed to have in the gas seems to only function sporadically.