Note that I have seen this issue on the original Get-VmsCameraReport and on the new one I just created a PR for that provides a more accurate retention when there are evidence locks.
When running Get-VmsCameraReport -IncludeRetentionInfo, sometimes a camera will show the UsedSpaceInGB but the MediaDatabaseBegin, MediaDatabaseEnd, OldestVideoInRetentionWindow (for the new function), ActualRetentionDays, and MeetsRetentionPolicy will be blank. In some cases, ActualRetentionDays will show a 0 instead of being blank.
The Warnings for no sequences being detected that get output for each camera when that command is run do not list the cameras that have the blank values.
I can't figure out how to consistently make this happen, but if I run the command below usually 1 of the 5 outputs will have the issue.
1..5 | % { $null = Connect-Vms; Get-VmsCameraReport -IncludeRetentionInfo | Out-GridView }