Exchange agent does not show data for Mailbox details attribute group or it shows wrong data for Mailbox details attribute group.
Exchange agent reads data directly from MailBox_Details.log located in agent logs directory. If Mailbox Details is not enabled in 1st tab of agent configuration window and MailBox_Details.log exists then agent will collect old data.
Resolving the problem
Make sure that "Enable Mailbox Details" is set to YES in 1st tab of agent configuration window and that MailBox_Details.log file is created at agent startup.