PDF getting created with permission 600 ?

Hello,

I'm experimenting a weird issue. Most of the time (almost everytime) my pdf are getting generated with the permission (rwx-r--r--) 644 which is correct. 

But 'sometimes'.. and I cannot understand why this happens but they get created with permission (rw-------) 600. this cause a "permission denied" when other systems try to copy or read the PDF...

Did someone already had this issue? Is it possible that is it a problem in my Jasper config ? or the Server config ?

Ps: I'm running my web app on an redhat server (container is Weblogic ).

Thanks !