night vision potion and waterfall

I've found two bugs that is night vision potion that for some reason sometimes the screen goes black surprise, I'm not talking about the game is removed but it means you can not see anything, but life, the hunger and the rest if the screen is black but is solved by putting a torch. And the other bug and has much in minecraft but I would like to get it resolved is that of when climbing a waterfall becomes very slow when moving next to a block and forgive me if I'm wrong on punctuation marks XD