wrote:
As long as the CFI is IFR current, has received a clearance, and is
ensuring they fly the clearance, it's perfectly legal. The regs do not
say which seat one must fly from. Whether or not it can be logged as
dual is another question that I'm not equipped to answer, but acting as
PIC is fine.

Yes, the student can log it as PIC (if they are the "sole manipulator of
the controls"). What the student cannot do is count it as part of the
required hours of instrument instruction towards an instrument rating.
It's PIC time, it's instruction received time, it's instrument time, it
just doesn't count towards the rating.