Shared memory permissions question

[Dmitry Agaphonov]

Hello,


I have user A from group G creating shared memory M with permissions
0060.  After this, A fails to attach M due to permission denied.
However, another user B from the same group G successfully attaches M.
User A manages to attach only if permissions 0600 added for M.

Why the system disregards group permissions for user A?  Is it correct
behaviour?

This is happening on FreeBSD 4.11-STABLE.

Thanks in advance.