Imported animation has bone flipping out wildly

UE4.11.2
FBX 2016 exporter

I’m getting this issue where my character’s neck is flipping out randomly throughout my imported animation. Seen below. Kind of like a turkey neck wobbling around. Yet strangely enough, the head (child of the neck) doesn’t twitch.

There doesn’t appear to be any funk or weird keys in 3ds max (graph editor), so I’m at a loss as to what’s going on here. Any ideas?