Moonstone isn’t using it. It’s not really a betta log, just a small white plastic cup. Is there a way to get her to use it?
If she doesn’t find it suitable, she won’t use it. You could try putting a piece of her food in it to see if she’ll get comfortable with it. Or maybe move it to another spot. But with my bettas, if they didn’t like it, they just didn’t like it.
She might feel that it's a source of danger, and won't explore it.
My bettas love the sinking ceramic logs, they are constantly inside of them.
My bettas love the logs as well! I think they like they can swim all the way through. My betta ElI sleeps in his log every night lol it’s pretty cute!