Yes, I've noticed that all the funnel smoke disappears (almost) whenever the water drops appear on the screen/periscope, and start over again. Then after 10 seconds or so, after which the smoke has reappeared, more water droplets hit the camera and the smoke disappears again.
I do use a mod to make funnel smoke show up at full distance, which is broken in the stock game - I don't know if this might be the cause of the problem.
I took a series of screenshots to illustrate it, but didn't get around to posting it in the bugs thread yet. I already put a ridiculous amount of things in there - it's quite tiring. I think we should all be paid by Ubisoft for our beta-testing feedback!
