RTF replace string logic corrupting document for viewer

I have an MDM interface with a DTL that takes OBX:5 and replaces "{\E\rtf" with "{\rtf" and "\X0A\" with nothing.  Most rtf's this works without a problem, some others, it corrupts the document.  

Code:

<assign value='..ReplaceStr(..ReplaceStr(source.{OBXgrp(k1).OBX:ObservationValue(1)},"{\E\rtf","{\rtf"),"\X0A\","")' property='target.{OBXgrp(k1).OBX:ObservationValue(1)}' disabled = '0' action='set' />

My question is - anyone know of any other "gotchas" that could possibly need to be replaced or something?

I have tried not doing the replace on anything, and the document shows up in viewer as just the rtf code rather a human readable document.  I am at a loss, any direction would be wonderful.

Thanks!