The Drekavac has a visual bug where if you zoom out there appears a black part between the front that disappears when you zoom in.
That’s most likely just the LOD kicking in and thus normal behavior.
That’s not how LOD works though. There is nothing there on the Drekavac when you look at the model zoomed in, or in stations and the preview.
If it was LOD there would at least be something there when you zoom in.
I noticed the same problem