I doubt this is the point they were making. But this just popped into my head. I wonder if, to Ahsoka, the relationship between them, that sibling-bond, is probably something she doesn't understand. The Jedi are, essentially, orphans. I wonder if it made her feel a little bit jealous? Perhaps Ahsoka interpreted, "He's my brother," as "He's my brother, so I have to go check on him. His feelings concern me, because we're really close like that." I think Anakin and Ahsoka have an unconventional relationship (duh), but I think the show is getting closer to the ramifications of this closeness they have.