When testing things for my server I tried using the /lp group group permission set pixelmon.command.pokegive true command to give my admins the /pokegive command, and it went through. But when attempting to use the pokegive command it did not work. It worked only once I used the /lp user user permission set pixelmon.command.pokegive true to give myself access. I ampart of the admin group, so it should have worked, But it doesn't, and if I run the group command again it says that the admins group already has the permissions in context global, but none of the admins can use the command.

Very unlikely to be a bug, you can use verbose to try to work out what's going on. :)

https://github.com/lucko/LuckPerms/wiki/Verbose