The Date: header on a message released from the Barracuda quarantine has the correct date, but GroupWise displays the received date, which is the date and time that GroupWise received the message.
You can have GroupWise show the Created date and this will correspond to the Date: header on the message. To add the Created date, right click on one of the column headings (ie From, Subject, Date, etc), left click on "more columns" and then add Created from Available columns to Selected Columns.
In most cases, the Created date will be the same or perhaps a minute earlier than the received date, but in the case where a message was released from quarantine, the Created date will show the date that the Barracuda received the message and the Date will show the date that GroupWise received the message.
If you display your Mailbox folder sorted by Created date, I think you'll see things in the order you are looking for.