Mobs not spawning after replacing realm world with backup

My problem is that no mobs are spawning in the world. I replaced my realm world with a backup and when I joined in I found a spider outside my underground base (in the mangrove where they shouldn’t spawn?). I have a pig, chicken, and sheep farm and none have de-spawned. I have gone far from the farms and still no mobs spawn. My creeper farm no longer works. No mobs spawn night or day. The spider and maybe a chicken is all that has (although those could have been there when I created the backup).