This looks like something your application is doing, not one of the background processes. Just look at the way the timestamps are being handled. Converting both to strings then trying to compare them. That is a really silly thing to do, and certainly not something I would expect Oracle to do.
I suggest you speak to the developers on your system and ask them what it is for, and also ask them to read about dates and timestamps so they can use them properly. http://www.oracle-base.com/articles/mis ... ervals.php