Did you get the scene where MC finds something in the Forbidden Wing? If not, you’re either missing part of the Weaver chain or you don’t have high enough secret stat. If your MC does find something in the forbidden wing but she doesn’t think much of it, you need more interpersonal insight.
You also need to get the garden scene in Week 6 before Avalie’s date to get the option to ask her about the Weavers.