strange
cant find an online repair manual for that scooter
could be the indicator switch itself
a bad earth
best start with checking the flasher relay and wire connections to it
loose or broken wire with vibration when motor running
maybe flasher itself
is ok when cold not ok when hot
or its overloading with the engine running
it could be a faulty side stand switch ,they a common fault,especially if it was running before you parked it.it will not bring a code up as its nt considered a fault,just that the stand is down.
talk with a service dealer for your bike as the gear oil is most likely used in the clutch as well and it is a special oil to prevent clutch wear or slipping
he will advise as to the quantity