Quote from Criminal Intent
For now Eba ignoring Haruto is basically just a plot device. I'm sure she'll clear it up eventually w/ some lame excuse just like the one Kanzaki first used (although later on she made a valid point).
It's doing it's job though. These last couple chapters have been making me very uneasy. Eba wants to distance herself, just as Kanzaki rejects Haruto, and now the Kikukawa is all up in his face.
I'm guessing (hoping) Eba is just planning some sort of surprise for Haruto, and thus the distance. The only thing that's suspicious is her hanging out with Kanzaki's brother.
The author is probably (hopefully) just trying to make it seem that she's distancing herself because of her plans to go back to Tokyo.
It's a compelling story.