2012 Q7 suddenly got the warning on the dash of a blown offside rear indicator bulb and the internal indicator dash lights are flashing fast when turning right - Fine, expected. The warning shows up every time the car is started after about 45 second of running.

However all external indicators are functioning and flashing at the right tempo! There is no blown bulb and the fast flashing arrows on the instrument cluster do not match with what is going on on the exterior of the car. Very odd. Took the connector in the boot lid apart, looked immaculate but gave it a clean anyway and re-connected but the issue remains. Hooked up an OBD to see if there are any fault codes and it's not listing a single thing.

I'm quite flummoxed with this one, does anyone have any wisdom to share?

Sorry to teach granny to suck eggs, but are you certain that all the indicators are working? I read of a similar problem recently where one of the mirror or wing indicator lamps had failed yet the front and rear main indicators were still working.

100%, I'll try get a video later if I can

Don't trouble yourself about the video, your words are good enough.

After that I am at a loss so let's hope somebody will have a suggestion.

Probably one of the led’s in the light cluster has/is failing and upsetting the canbus. Put the hazards on and check to see if one of the led’s is slightly dim or off.