When the problem is related to the zoom setting, it doesn't have anything to do with the Anti-pop setting.
It's the fact that cars use LOD for obvious performance reasons and, when you use a too wide zoom level, the lowest LOD (which means "disappear") kicks in. We usually optimize the scenery for the most realistic zoom level which, according to many tests, it's around 0.70.
This can't be tunable like the Anti-popup, which only controls the loading of the objects, not the LOD switching, and its relationship with the zoom level is out of our control. If we turned off LOD, just to let see such objects at all zoom levels, it would slow down performances, which is not worth, considering cars aren't something really needed when taxiiing.
So, it's not a bug, it's just expected considering how the scenery is made, not everything will show up at all zoom settings.