I have experienced the same problem!!!!
Conecting the PTZ video camera through 2 transceivers the video works but the ptz does not.
We changed the fiber and.... it works. But the interesting thing is that there are not any other connections in the fiber. There ar just the 2 pigtails (connected by fusion).
The funny thing is that the video is shown properly, but the ptz not, and it is not a bending issue, we have taking out the fiber (it is just 300 meters) and it neither works with the fiber in perfect conditions....
Any idea about why this is happening? Both fiber cables (working and not working) are from the same supplier and same reference...
I never seen something similar to these!!!!
Regards