Sony FS700 Slow-Motion

I recently filmed a bunch of footage on my Sony FS700 camera. All of it was recorded at 1080p and 240fps.

I have imported all the file into Adobe Premiere Pro and edited the footage. Everything looks great.

However, after exporting (H.264 at 1080p), there are a few clips that don’t have the smooth slow-motion effect. They look more choppy as if it was shot at 60fps and slowed to about 10%. Anybody know why this is occurring?

Here’s a link to the video: https://vimeo.com/120497885

It’s noticeable from 00:33-36 // 00:40-00:41 // 1:11-1:16 // and 1:20-1:26

Any help would be much appreciated!!