Hope the role that you have added contains only one permission:
Object S_DEVELOP ACTVT = 03 DEVCLASS = * OBJNAME = * OBJTYPE = DEBUG P_GROUP = *
Try to perform a permission trace usingTransaction ST01
If you still don’t find a check for the permission, there might be a problem in generating roles in the system. Sometimes when you add a role, it might add a different set of roles to such users.
There might be a different program written for Debugging. This can be checked using Transaction SU53 in the system. This can be used to display authorization data for user: