Phasor is a server extension for Halo PC which focuses on giving the end-user the ability to deeply customize gameplay. Phasor does this via its scripting system, which uses the Lua language. Scripters are able to react to and change many different aspects of the game.
Ah yeah, that's a Phasor bug. PC uses chat mode 3, and on CE that is server chat. I'll check if other modes work to remove the \ SERVER **, I assume 4 will.
The boolean to disable the prefix is not working for CE. I used the same script for PC/CE and it only occurs on CE.