Interesting problem. Questions...
What DP version is the Cell Manager (CM)?
What DP patch level is the CM?
Is the DP GUI running on the CM?
In case the DP GUI is not running on the CM...
What DP version is the GUI system?
What DP patch level is the GUI system?
If the GUI is not on the CM and the CM can run a GUI (it is a windows CM, not linux or HP-UX), does the CM GUI show the same problem?
Another approach to look at this problem would be to run CM cli commands to see if that shows the same values.
eg.
omnimm -list_pool "[PoolName]"
omnimm -list_pool "[PoolName]" -detail
omnimm -list_media "[MediaID]"
omnimm -list_media "[MediaID]" -detail
omnimm -media_info "[MediaID]"
omnimm -media_info "[MediaID]" -detail
Then you should know, the problem is within the DP IDB or within the GUI.
If the DP patching is not up to date, I'd say patching should be an early step.