There is a problem in stereo 3d output

When I use stereo 3d render (anaglyph/side by side/above below or dual stream) the problem is rendering only 50% of shot length

For Example


Timeline is 500 frames (30fps)
when I export in normal without using stereo 3d its render 250 of 250 its perfect

But when I use stereo 3d output its renders 125 of 250 exporting 50% of shot length

Please go through yourself and please reply soon,

know one responding properly for this issue please help us to fix the issue