Dear Jim,
I was able to reproduce the issue that you observed with exported Custom Inventory report, this could be a bug in the system, I will validate a few things and confirm.
As a workaround you may want to look at offline custom inventory report. You can request this report from Actions - Schedule Reports - Select Custom Inventory Report from the drop-down.
The report has a tab Custom Inventory that should show collection date and hardware alert.
Regards,
Suchita