Hello!
I had a similar issue with Metahuman eyebrows when doing close-ups using long focal lengths like 150mm. It was related to the near clip plane of the camera.
In my shot, blocks of the eyebrow hair would disappear (like they had been shaved off). And it would change if the camera moved.
In the camera Details, I checked Custom Near Clipping Plane, and increased the value from 0.1 to 1.0 (or maybe even higher as long as it didn’t clip anything out of the foreground of the shot).
There is also Near Cilp Plane setting in the Project Settings. Changing it will affect other cameras like the Perspective camera in the Viewport, which might not be desirable in this case. I prefer to change it in the camera settings, not the project settings.
I hope this is helpful!