Hello! I'm Not Sure where to Post This, But here is the Guide on How to Fix Professor Fig's Bug in the “Follow Professor Fig” Quest.
1. Try Restarting your Computer (If This Doesn't work See Below;)
2. Uninstall & Reinstall the Game (If This Doesn't work See Below;)
3. (Windows) Click on Hogwarts Legacy on steam, Find the "Browse Local Files" and Click On That, Then Delete all the Contains of the Folder and Delete the Folder, then Uninstall & Reinstall Hogwarts Legacy.
It Should Work Fine Now. 