When adding users via /whitelist add [username] and /op add [username] the UUID added to the appropriate .JSON file is incorrect.

For example: (partial UUIDs shown)

entry in whitelist.json for my account (whitespace removed):

{"uuid": "d1f1d2aa-17d4-3100-8062-", "name": "cameramonkey"}

Entry in my server log when I login with my whitelist off:
[19:48:35 INFO]: UUID of player cameramonkey is 96854272-193e-429f-

If I copy the UUID from the server log from when I attempt to log in into my JSON files and replace the UUID the server created I can log in. If I login without touching the UUIDs the server added from the /whitelist add command I am told I am not whitelisted.