RE who writes these things: I know you're probably referring to code here but on the actual dialogue side, there was a charming interview recently with the person responsible for translating Miyazaki's vision into English. He apparently did all of the writing (dialogue, item descriptions, UI text) for Dark Souls, and split the work with just one other person for all the later games including Elden Ring.
https://youtu.be/vIbKALhzHVc?si=WRAQs77WG2QwVkt5
More topical, I do actually appreciate some of the persistent jankiness like this that hasn't changed since their original games. They experimented with different approaches in DS3, where certain NPCs you encountered would essentially evaporate after you exhausted their dialogue, and they would later materialize back in the hub. I personally hated this -- one element I really enjoyed in the earlier games was this sense that the world doesn't revolve around you. The NPCs feel like rich characters with their own goals and motivations
Having them leave when you're finished talking to them sort of reduced them to utilities, which of course they are ultimately, but the gamefeel suffered a bit from making that more explicit. Don't me wrong though, I love DS3, but I didn't care for that particular change
Anyway, handling NPC progression in this way where the player needs to reload the area is more about navigating a technical limitation than anything else. But like many constraints it conspires with others to produce a certain gamefeel that I enjoy. It would feel a bit less impactful if Hyetta just moved on the instant I exhausted her dialogue -- it's more interesting for me to return and see that she has moved on
Another example of this sort of thing is FromSoft supposedly historically being bad at animating eyes, hence many critical NPCs being blindfolded or with faces hidden by helmets or otherwise obscured. This imagery plays nicely with their other sensibilities around character design and is thematically pretty rich