no issue at all. Gear shifter sensor/gear selector sensor is bad. It is located on the gearbox opposite the radiator fan, many times the sensor it self goes bad & in some cases its wiring harness doesn't gives proper signals to the sensor.
Faced same issue in my vitz 2000 back in 2015 and I even got the complete gearbox replaced on our desi mechanic's advice, but the issue was still there. Khair we solved the problem by replacing this sensor as well as its wiring harness/connector afterwards.
I dont have any pic of that sensor, to explain you better about its location.
The sensor doesn't cost much, should be around 2k.