Why do LTE data speeds slow down iPhone 5 is connected to Lightning Adapter?

I have asked similar questions about slower data speeds before, (New Lightning AV adapter) but I am starting to notice a trend. When I have my phone plugged in using my lightning adapter to USB wall charger (or any other lightning adapter) my LTE data speeds slow down significantly. I am starting to wonder if these chips inside the lightning adapters are causing problems. Is it possible that the phone and the adapter are busy communicating, which is slowing down data speeds? Has anyone else noticed this?