Okay, I think we’re coming down to isolating the problem.
Could you review this KB article by @sineos:
What are the electrical/physical changes that you’ve made to the printer? In the OP, you say you ‘performed “maintenance” work on it, which consisted of replacing the CAN board’ - what exactly did you do?
If I’m reading the situation correctly, there’s something happening that causes the stepper drivers to reset, which was originally identified as unable to read IFCNT but it’s actually a driver reset (which is the GSTAT error).
Going back to your klippy.log, it looks like you are connecting to the Octopus via USB and the Fytsec toolhead controller using CANBus. I’m guessing you’re using something like a CANable board to provide a USB to CAN interface for the Fytsec toolhead controller.
Could you confirm this is true?
Now, what did you have before adding the CAN board and how are you wiring it into the system?
What was the process you used to set up the printer with the CAN board?
You might want to disconnect the Fytsec board and the CANable board from the system as well as make a “dummy” extruder entry in your printer.cfg and then do your G28 X command to see if the GSTAT problem goes away.