Invalid permissions set for newly created directory

Question

This is the code creating the cache folder with the wrong permissions:

mkdir($saveFolder, 02775); 

When I check folder permissions using ls -la , I get:

 drwxr-sr-x 

But instead, I expect:

 drwxrwsr-x 

Answer 1

For some unclear reasons (at least for me) changing the code to

 mkdir($saveFolder); chmod($saveFolder, 02775); 

solved a problem.

Now I get the correct permissions set in the folder:

 drwxrwsr-x