Needs action even if the appointment was accepted
we have a Zimbra NE 7.2.3 installation over Ubuntu 10.04 64bit.
We encountered a little problem.
We created an event with about 15 participants, everyone accepted the event but someone is shown as "Needs action".
I attach a screenshot of the scheduler (sched.png) and the popup of a user's event (app.png), the user accepted it, but is shown as "Needs action".
I tried reindexing the mailbox and flushing account cache but no effects.
What could cause the problem?