Animations different in engine?

I’m wondering why my animations are appearing quite different in-engine than they do in 3D Studio max.
I’ve noticed that some of the curves seem to be different so the animations don’t line up with each other properly once imported and some of the translations are being lost, specifically rotations. I created a video and slowed down the animations to show the difference.

Essentially UE4 is messing up the bone rotations and the curve for the animation isn’t being maintained so parts of the animation are slowing down and then speeding up and then slowing down again.
I chose to bake the animation when exporting the FBX but this didn’t help.
I’ve also attached a screen of my FBX export settings.

So I was able to fix the issue by manually adding a key frame for every frame of the portions that were having issues. I thought baking the animation on export did this, but obviously not as well as doing it manually.
Would still like to know why this happens as with an 800+ frame animation this is very tedious to do.