It appears to be a practical decision from my point of view. Jun can't train outside of Korea because he's a university student there and he has to keep studying there in order to get funding and remain on the Korean team (I hope I've got this right, @Ichatdelune).I just watched Jun. Oh, my. It has shades of the French Grand Prix disaster Shoma skated when he was without a coach.
I'm sure it's discussed elsewhere, but I wonder why Cha left Orser? I didn't know he had.
As a Shoma fan, I don't think this was quite as bad as the IdF disaster, though I don't want to think about what Shoma did back then at all. Jun...still had that beautiful Ina Bauer going for him...