It is simple to reproduce this bug.
-Load into editor, any map or setting will be appropriate.
-Create an autorifleman unit, or acquire a 'Zafir 7.62mm LMG'
-Attach an ARCO, RCO or MRCO scope to the 'Zafir 7.62mm LMG'
-Go into the 'Crouch' stance (Default X)
-Use the magnified optic on the ARC/RCO/MRCO, and MOVE AROUND while using the optic.
This video shows the issue as well as briefly how I reproduced it.
http://youtu.be/lI-vWwUFefQ
https://www.youtube.com/watch?v=lI-vWwUFef