Kerbal Space Program

While running uphill on Kerbin, the Kerbal will gradually sink into the terrain. This causes the "[F]: Climb" prompt to show up. If I stop running, or press "f", the Kerbal will reset to the top of the terrain. This behavior is exaggerated while under physics warp, but physics warp is not the cause as it happens under normal time acceleration as well. I have attached 3 pictures showing the Kerbal sinking into the terrain under normal time and under 2x physics warp. The third picture shows the Kerbals demise as they sunk into the terrain. While the pictures show mods, I confirmed that this behavior also happened under a clean install of 1.8