What is the PRPC version you are using ? With which control you are displaying the field values ?
I believe there is a hotfix (Hfix-22332) for PRPC 7.1.7 which addresses the issue. A change was made to "Validate" activity of Rule-Obj-FieldValue class to do a filterRichText (intended to remove unsafe tags like script tag). This change displayed encoded values of quotes in controls like checkbox and dropdown. This happens because of the double encoding since these controls already do a crossScriptfilter.