Make sure the RFX units have the latest firmware. You did not mention what firmware you have on either the RFX or the 9800's.
Here's something you might want to experiment with.
Have you also tried putting extenders in Network Mode vs Standalone Mode? If you do this, consider using Fixed IP addresses for each of them and configure the fixed IP address setting in PEP2. By doing this, you avoid extender discovery steps.
