AI invisible

Something is happening with my AI - well one plane for sure. When I click on the drop down menu for views and click on AI Traffic I get a full list of planes that I should be able to see in the area. This is all good. However, I have a Fokker 28 that keeps showing up on the list, but when I click on it, the plane is invisible. You just can't see it. You can pan around it as if it were there, but it isn't there. Anyone have any suggestions as to why this would be?

Thanks 😀