are you using 2.1 ? if so, is it possible that your container is flushing any updates made in the same transaction, before the finder method ?
is this using 3.0 with jpa ? if so is there any code before the find that may force the jpa provider to flush (partially or totally) the persistence context so that the find may be satisfied (which you can confirm by activating the verbose sql trace generated by your jpa provider).
if possible, i suggest that you try commenting out the call to the finder method and just finish the transaction (by returning from the calling method). check that the problem remains. this would indicate that there is something wrong with the way your application is modifying the data.