(Unity)Logic Control leads to 3D Attributes error? why?

I can’t figure out why it happened. I need help!
We need an engine sound in our Unity project. I use logic control to simulate the process of engine. But after I added the logic component in FMOD, the weird error happened: the object with engine sound can’t locate the 3D Attributes correctly any more!
I supposed that the engine sound should always follow the character. But after the first time it has played, it can’t follow the character anymore.
I monitor the distance from the engine sound to listener(the camera) with this code:
Debug.Log(" Distance: " + (Audio.transform.position - Camera.main.transform.position).magnitude.toString())

But it shows that there isn’t any abnormal data with it.
The logic component I added in FMOD is “Loop Region” and “Transition”. Only if I remove them from the engine sound, the error doesn’t happen.
Unity Version : 5.3.4f1
FMOD Version : 1.09.06
So how can I fix this Bug?
Thanks a lot!

Are you getting any warnings or errors in the console log?