[AccessD] Data on Report does not match data in the Report's Record Source

All,

I believe that this is the strangest thing I have ever seen in Access
2007.

We have a purchased package which uses a Firebird Database. All of the
tables are defined by the application vendor.  We are able to access the
Firebird tables from Access 2007 via ODBC.  This combination has worked
nicely in numerous tests that we have conducted over the past 2-3
months. 

A few days ago, I happened to notice that the data on one report does
not match the data in the Report's Record Source (a query).  I have
conducted many tests on two different PCs and the results are
consistent.  The data on the report is correct, but the data in the
underlying Record Source is not correct.  If I look at the Access
"Linked Table" (Which is stored in the Firebird Database), the data is
not correct (but I can make it appear correct by doing a Refresh in
Access). 

If I view the data with the Firebird Utility called "isql", the data is
correct.

I have spent many hours trying different things and running various
tests (and pulling my hair out).


In summary...

Data on Report = Correct

Data from Firebird "isql" utility = Correct

Data in Report's Record Source (query) = Not Correct

Data shown by viewing "Linked Table" = Not correct (although I can make
it appear correct by doing a "Refresh" in Access) 

Data as viewed via the purchased application = Correct

We have conducted many tests with the Firebird Database - Access 2007
combination over the past few months, so we have some experience, but
not a huge amount.

My latest theory is that the problem lies in the ODBC driver.

This would explain why the data appears correct with isql but appears
incorrect when initially viewed as an Access 2007 Linked Table.

However, this still doesn't explain why the data on the report is
correct when the data in the report's record source is incorrect.

Has anyone ever heard of anything like this before?

Has anyone worked with Access in combination with data from Firebird
database tables?

Thanks for your help,

Brad