Minecraft Version: 1.21.8
Plugin version: 1.12.3.2
The problem is that writing the command /claim with a non-existent argument (invalid argument) throws the message "You don't have access to this command" which implies that the argument/command would exist, but you just don't have the right permission.
A better way to handle this is to give the user the right feedback with a message like "this command doesn't exist".
How to reproduce:
Type /claim afhehsfukhserf
(any non-existent argument)
How is this a problem?
When users try to access commands they think could exist, like /claim gui (which doesn't exist). It should give them the right feedback so they don't get misled.