We've discovered a find / replace bug.

If, after performing several sequential find / replace operations (approximately 5-10 different, sequential operations) the next find / replace fails.  The failure is instead of replacing the selected text with what I desire, it is replaced with nothing at all.  It also replaces the REPLACE field with a blank entry.

One might say it is not "failing" but wiping out the correct text in the REPLACE field with a blank entry, and then doing REPLACE.