Row values changing back to old values randomly???

Has anyone every seen the following behavior?

Oracle 9.? running on AIX, no problems here Windows NT machine,
Oracle client installed on the NT machine with ODBC driver v 9.2.0.2

We have set up an ODBC source on the NT machine. An application (app server) opens a connection pool with e.g. 4 read connections and 4 write connections.

An application changes e.g. two rows in two different tables and commits.

The changed data is visible in TOAD from another machine.

After about 2 minutes, the data is reverted back to old values without any activity from the app server whatsoever.

How is this possible? Note, this is definitely not a bug in the app server code because the app runs without problems on 3 other Oracle database installations and on many many other installations using PostgreSQL, SQL Server and DB2. The app doesn't even know what the old row values were!

Has anyone ever see something like this happening and how to solve it?