The term "belt guide" isn't very helpful, especially given "...the car is running fine...".
The pulley on the A/C compressor is the drive portion of the setup, and freewheels until the controller calls for the compressor to run. Once the electromagnet is energized, if the system is working correctly the drive pulley then starts to turn the driven hub on the A/C compressor itself.
The car seems to be in service, so I'm a bit confused about the actual situation here.






