mailbox full size but I can forward email

Groupwise 8.0.3 HP3 I have some mailbox with the quota exceded, They can't forward or reply emails but if They define a forward rules all emails can be sent to another destinations (internal or external to groupwise system).

I want to know if this is a bug or a need to define some configuration to block all when mailbox size is exceded .. Forward, reply, forward with rules, etc.etc..

Thanks

Vanessa
email: vanessav@it-synergy.net