I really appreciate you adapting the change for server uuid. I came across an issue that i wanted to bring to your attention as well, looks like users not in the cache (server uuid), show user info: unknown for a name, and you cannot change the primary group from the original value.

lp user ScarletRed89 switchprimarygroup diamondlevel [23:05:04 INFO]: [LP] 9ca68b17-cb66-4fd0-b4c9-4443be5772f8's primary group was set to diamondlevel.
[23:05:04 INFO]: [LP] (User data was saved to storage)
lp user ScarletRed89 info
[23:05:07 INFO]: [LP] > User Info: Unknown
[23:05:07 INFO]: [LP] - UUID: 9ca68b17-cb66-4fd0-b4c9-4443be5772f8
[23:05:07 INFO]: [LP] - Status: Offline
[23:05:07 INFO]: [LP] - Primary Group: default
[23:05:07 INFO]: [LP] - Counts:
[23:05:07 INFO]: [LP] - Permissions: 2
[23:05:07 INFO]: [LP] - Temporary Permissions: 0
[23:05:07 INFO]: [LP] - Prefixes: 0
[23:05:07 INFO]: [LP] - Suffixes: 0
[23:05:07 INFO]: [LP] - Meta: 0
[23:05:07 INFO]: [LP] - Parent Groups:
[23:05:07 INFO]: [LP] - > commissioner
[23:05:07 INFO]: [LP] - > diamondlevel
[23:05:07 INFO]: [LP] - Cached Data:
[23:05:07 INFO]: [LP] - Has contextual data: false
[23:05:07 INFO]: [LP] - Current Contexts: None
[23:05:07 INFO]: [LP] - Current Prefix: None
[23:05:07 INFO]: [LP] - Current Suffix: None

This is because there is no "player" record for the user until they've joined the server.
A nice quirk of the workaround with the uuid resolving option, I guess.

You can fix it by using a different primary group calculation method. (you should probably do that anyway)
https://github.com/lucko/LuckPerms/wiki/Configuration#primary-group-calculation