Out of Office works after couple of hours in Outlook

Hi

I've received many notifications about out of office in Outlook 2010. My environment is Exchange 2010 SP3.

Many users set their out of office message, set rules and they notify me that it isn't working.

When I check it is true. Nothing appear in my Outlook tip and rule doesn't work when I send message to this person.

After some time it works.

I don't know why this isn't works fine.

What I could test or check to resolve this issue?

Thanks for replys

Pit