In prior 1.17.1 version CraftBukkit version 3276-Spigot-3892929-b58f429 (MC: 1.17.1) (Implementing API version 1.17.1-R0.1-SNAPSHOT) and vanilla 1.17.1 and 1.18 version the player UUIDs match when logging in.
For this version, the player UUIDs are different when you log in.
If I use /whitelist add <playername> it pulls the correct (old) UUID (from where ever it does that). If I join the server, it uses a different UUID.
This is impacting whitelists and bans (not sure what else) as the player UUIDs no longer match up.
Image good UUID shows prior Craftbukkit version and it's the same in vanilla 1.17.1 and 1.18.
Image bad UUID shows current version (as shown in version.