I experience the same. Try flying into Chicago without AIG Traffic Controller with default Asobo Live Traffic.
The only issue I could think of, is the sim is starting to enforce LODs handling as Asobo promised it would start to do last year after SU5, but it was never really added other than in DevMode, because when it was announced, it spread a mass of complains from scenery developer that feared they would need to redo all their scenery to add LODs, so it was restricted to XBOX only, which has less memory than a PC.
Basically, the simulator decide if there are too many objects in memory and will start removing them automatically, starting from the ones without LODs, then proceeding with the ones with too few LODs ( less than 3 ) leaving the ones with 3 LODs or more as the last one being removed.
This will probably affect like 90% of the airports out there, since nobody really used LODs before but, possibly, it wasn't a problem until recently, when more and more products like AI traffic packs have been released, increasing the chance that, on a large airport, the automatic LOD handling would start to remove things.
It might be interesting to test AIG with KCLT. Since it was released a couple of months after SU5, it was heavily optimized with multiple LOD levels everywhere because of the above "LOD scare".