Bug: Falling into water doesn't reset the lemming's fall height.
Severity: Annoying, potential to cause level fail state.
Each Lemming maintains its own counter to see if it should splat or not when it lands, which increases as it falls, and is reset when they land. Unfortunately, if the lemming is a swimmer, he can fall any distance into the water and survive, but this does not reset his fall counter. This means the lemming is now susceptible to die from very small drops.
The good news is, that there is one way to safely reset the lemming's fall counter, and that is to enter the state where you pick a direction from using a spade or brick tool. You do not have to ultimately choose a valid direction, just enter the direction picker mode, and his fall counter gets reset. Unfortunately, no other skill or action works to do this. Level designers, take care to try and ensure the player always does this after a long fall into water.
See attached animated gif for a demonstration.
There is one other situation where the lemming checks its fall counter, and that is when to open its umbrella, but if you have already passed this distance, the lemming will
completely bug out. (Note: this is the same video in the previous post).