Thanks to everyone who responded to this problem.  It seems we have an
undocumented issue here.  I was on the phone with Level 1 (highest) support last
night for a different issue and brought this one up while we waited for some
processing to run.  I was told to document as much as I could about the tapes
before and after they disappeared as well as how I am discovering them.  I am
doing so.  I suggest that everyone else that is having the problem do so also.
I am finding them by running a report of all of the volumes in the vault, and
vault retrieve states and comparing the total to the number I know are in the
vault.  When there is a discrepancy I compare the two lists.   I have started
running the output of a "q drmedia f=d" to a file every day and holding it for
about 7 days.  That way I have a history of the file before it disappears.  I am
going to collect several instances and then open a case with ADSM.  Everybody
else that sees this happen I urge to do the same thing.  I think we all want
this problem addressed!

Thanks,

Scott