Does it generate a bug report? You can check by going to the prefs folder listed at the bottom of the C4D Preferences dialogue. There should be a bug_reports folder there. Check the date/time of the files, if there are any. If there are, send them to Maxon tech support and they may be able to tell you what the problem is.
How about using a Random effector set to turbulence or noise in global space? Use in combination with a particle wind effect? Turn up the Dynamics tag’s Aerodynamcs: drag and lift parameters for a more pronounced effect.
On second thought it looks to be a little more complicated than I thought. The axis of rotation essentially changes because the mechanism uses a second set of rails at the top and bottom. Here’s a good illustration that was probably done in C4D: https://vimeo.com/5196298 You might contact Joel and ask him how he did it.
Meanwhile, here’s another quick attempt using a couple plane effectors at the top and bottom to get it closer to the mark:
You should be able to do it with the spline effector, but I think it’s a matter of getting the correct axis position/rotation for the clone. Here’s a quick test I did where the axis is off, but moving in the right direction as it were….