f-curve cycles modifier giving odd values

I’m having some trouble with odd values for animating along a path.
I’ve set up a few key frames and I’m using the cycles modifier to repeat them.
However, the value ‘Evaluation Time’ value occasionally jumps ahead and then back again resulting in the object following the path to jump forward and back.
The attached blend file demonstrates the issue. It first occurs on frame 121 but playing the animation through it is visible several times.
The blender file contains just the path and a a cube to demonstrate the issue.
This is the first time I’ve used the cycles modifier so I don’t know if I’ve just missed something simple?
Any help appreciated.


pathError.blend (460 KB)

I have looked at your file and cannot see anything unusual happening around frame 121. The cube moves at 2 speeds in a cyclic manner as shown in the f-curve. What are you trying to achieve?

Thanks for your reply - as a result I ran the file in the regular version of blender 2.75 and it also ran fine.
I was using the cuda optimised build which gave the problem.
Wasn’t quite expecting those sort of errors between the cuda and regular builds but lesson learned.