The MB400 scanning module may not always report oldest message age correctly.
If the MB400 scanning module reports the oldest MPDU with a negative age (in the Message Count field), you should edit its configuration file to change the following lines:
AgeSeverity1=3 AgeSeverity2=4
Edit the error levels so that these two lines read as follows:
AgeSeverity1=1 AgeSeverity2=1
The scanning module will still report the information, but Monitor Records will not be displayed as an error or fatal error (severity 3 or 4).