I've spoken many times with former SCOTUS clerks, and I've read several books about the Court's operations. Thus, while I'm no expert, I do have a pretty good idea of how the Court works on a day to day basis.
Justices spend 95+% of their time holed up in their private office reading and writing. They pass extensive notes between chambers, typically in longhand. But the Justices rarely see each other face to face, other than for a weekly conference and open Court sessions. Ginsburg has been skipping the open Court sessions, but has been participating in the conferences. I don't know whether she's attending the conferences by video or voice only, but I'm pretty sure an intern isn't standing in for her.
It certainly is conceivable that Justice Ginsburg is relying more on her interns than usual in preparing for the conferences. It's also possible that she's passing fewer notes than usual -- or maybe not. I suppose it's even conceivable that she is having interns write her notes, but I find it hard to believe that is happening.