World files are not being reused through multiple sessions on a Minecraft Realm. I noticed previously loaded chunks not appearing and investigated the bobby folder. Multiple world files with the different seemingly random ip addresses have been created all sharing the same number as the storage folder. In my case I have 5 different ip folders carrying world information for the same realm after only playing ~10 sessions over 3 days. Rapidly rejoining a realm after leaving seems to "keep the realm alive" and the ip stays the same.

Recreating this issue:

1. Install bobby
2. Join a Realm
3. Wait an amount of time (long enough for the Realm to go into sleep mode)
4. Rejoin the Realm
5. Notice two ip folders with realm world information