I'm pretty sure the only answer I gave that wasn't the one that she wanted to hear was the one about the pen. It only turned grey after I hugged her though (which is a lot later as you know).
I also checked that right before the hug it's colored and after the hug it's not.
I didn't try to make a 100% walkthrough playthrough yet, so I don't know if this actually always happens. Thanks for looking into it^^