No, she changed it once and now she's changing the episodes after. With Ep. 14 she'll have changed the next episodes. Step by step like she said in her updates. She wasn't happy with the assets she used in the beginning and her setup wasn't up to date. Now she has the money for the assets she wants and she bought a new setup before Ep.10.5.
Tipically this was more about houses and locations, girls looks may have improved with the graphical changes but the basic character templates stayed the same, including hair colors(even for Melissa until recently).
Melissa being the person who already uses colored hair makes her an easy (in universe) character to keep changing, allowing Nyx to get creative.
That and the fact that her route(this one more real world fact) that her route is still on it's infancy.
Changing the girls that people built deeper relationships and (suppousedly) stuck with their natural hair until today would create bigger backlash.
I don't know if it's intentional... but Nyx gave her the "midlife crisis" package, 40 something woman who can't stop fiddling with her hair...
Being horny and not acting on it can do that to a lady lol.
Hopefully it gets written into the story lol.