This was a pretty nasty but that I think would only happen on slower machines.
The wind force was weaker if the computer was slower which caused the jumper guy to get stuck and sometimes fall to the bottom of the hole where he could not get out.
This should not be fixed. The wind force should be the same even for slower machines.
Sorry for any headaches this may have caused.
Special thanks to Petríček for bringing this but to my attention and giving me further info to help fix it.
-Jeff