All the other Perl changes suggested are good ones but the core of your problem is the find change suggested by zengargoyle. Without a -depth argument to limit the find you're actually getting more directories than you assumed. You're actually probably seeing the following (all directories):

/home/sites/$arg1/users/XY/
/home/sites/$arg1/users/YZ/
/home/sites/$arg1/users/YZ/bbb/ 
/home/sites/$arg1/users/BD/
/home/sites/$arg1/users/BD/ss/ 
/home/sites/$arg1/users/GD/
/home/sites/$arg1/users/GD/gg/ 
/home/sites/$arg1/users/ZX/
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