I dont think that will be a problem, as they will likely designate areas around towns as being fairly low level, or, once you cleared/captured the town, they would prevent such high level monsters from spawning until your settlement reached a high "rank" or something.
Skyrim had a similar system in place, were certain dungeons had a minimum level set, such as the tombs of the named dragon priests where always set to level 25. Even if you went there at level 1, the place would be set at level 25. However, if you were over level 25, the place adjusted to your level, just the same as places without minimum level sets.
I doubt any outside area will get stuck at any one level for the whole game.
And that is why its bad.
That doesn't really change the situation much though, the game is still playing itself, which defeats the point of you playing it.
Because it wasn't a mistake. The point of games is to have fun, not to throw [censored] in the player's face because of "deadlines" or w/e. That is why 99.99% of games(again, a figure of speech here) dont do that sort of stuff, and the ones that do only do so to cater to a niches.
Having a game that has NPCs that complete dungeons is like buying a box of your favorite snacks, and then being told out of the 100 packages of said snack that were advertised in the box, 20 of them are gone because the snacks can eat themselves, and then being told by the company who makes the snacks "WELL DATS JUST DEM BREAKS!". Its like, why the hell did I bother paying for a 100 count box if I am not getting 100 of those snack packs?