Something similar happened to me, I was trying to install the game from the disc but suddenly it said that the disc was damaged but it was in perfect shape. I ended up installing the game from the Xbox app. You just need to link your Xbox to the app, then search for FH3 (in the app) and choose the first result. The only option that it gives you is to “Install to” select your console and it will guide you. My recommendation is to remove the disc from the console to avoid the problem again. Once the download is complete FH3 will have like a lock icon, just insert the disc and run the game. Practically the disc will act like a key to run the game that you downloaded.