Seems like water + speed is the issue. If water splashes into the air intake, there are holes in the bottom of the air box for it to drain out. However, if you're doing anything to cause the engine to realllllllly breath while water comes in, the faster airflow isn't going to let the water go out the bottom.She's a stock JK Rubi and can climb anything I point her at...water seems to be an issue.
I changed my air filter for the first time yesterday and about crapped when I saw lines from where mud had gotten sucked in and drained out the bottom. I'm sure if I was gunning it through the mud, that stuff would have going straight into (and thru) the paper filter.