Yes Lu/Mitrofanov kind of lack expression. It's been said before that one or both of them are really into academics and this split rumor has been out there for a while, so I'm not that surprised by a split, but still surprised.
Despite their technical improvements over the years, they had some persistent lifting issues after 6 years together. Audrey grew to be relatively tall for a pair skater (about 5'4") and they were managing it, but only they know what training was like on a daily basis. Audrey originally came from singles and maybe she wants to continue it until college (which would typically start in the summer), who knows.