Sammie is still not happy about the interloper. She’s not as wary of Frodo as she was at first, and has taken a couple of swipes at him. Part of the problem is that Frodo isn’t the slightest bit intimidated by her and keeps trying to attack her tail. If she chases him, he chases her right back.
I think it’s a communication problem. Sammie just wants him to leave her alone, but Frodo thinks they’re playing a really fun game.
Sammie has taken to finding some high ground to escape Frodo, and from where she can keep a close eye on him. The top of the bookcases is one of her favourite spots for that at the moment.