Hey guys, I had the same issue. I've tried to follow a lot of pieces of advice and something(I dunno what) worked. What I did:
1) Updated OBS and set correct settings
2) changed compatibility of the game to Windows 8( You can try windows 7 or 8)
Probably it influenced this stuttering
3) set low settings in the game
U can also try changing priority of either game or OBS.(or both)
That's all! If I helped you, u can subscribe my twitch channel. I will be grateful for this:) If I didn't help u, sorry.