This might be due to the following things:
- You have disabled the "Advanced Animations" flag in the FSX Graphic options. Be sure it's on.
- You are looking from too far distance, or with a too wide zoom setting (or a combination of the two). FSX automatically disables animations after a certain eyepoint distance from an object, to save performances, and this depends on the object size so, it might appear earlier on small objects like the marshaller. We don't have any control on this, but zooming in or going closer with the viewpoint should fix this.