Missing Disk Partition Tables on Windows 2003

This is interesting .. have seen this on a number virtual and physical windows 2003 servers, with NetApp or EMC storage.

For some reason, external storage is goes missing after a reboot.  I does appear in disk management, but as an initialized disk. 

So far we have found that if you use testdisk, you can recover the disk partition from the backup and get the data back, but it’s damm weird .

Anyone else seen this?