The Encounter Zone Recalculation (Continuous Level Scaling) mod is a very simple way to fix the scaling of the encounter zones.

The reason for this is simple: the game is designed to keep the quality of enemies and loot the same no matter how many times you've cleared a certain location. So, if you go through a location a bunch of times, you'll be getting the same quality of enemies and loot regardless of how many times you've gone through that location. This mod is developed to counter that and ensure that you'll encounter enemies and reap loot that's appropriate for your current level.