Hello Michal,
locateReflectancePanels method should automatically mask calibration panels and put the related images to the "calibration images" directory in the chunk's contents. Do you see that, if the project is saved after the script run and opened in GUI mode?
Also please note that reflectance values for the panel should be input "manually", if they are not coded in the QR code. Using Python it should be possible to assign the values in the following way:
albedo = {"Blue": "0.65952", "Green": "0.67788", "Red": "0.67718", "NIR": "0.66653", "Rededge": "0.6223266"} #panel values
for camera in chunk.cameras:
if camera.group.label != "Calibration images":
continue
for plane in camera.planes:
plane.meta["ReflectancePanel/Calibration"] = albedo[plane.sensor.bands]