Hy Andi....Have you find a solution for the problem? I have the same problem with the LEDs 96680961AA on my Ducati Monster 821 MY 2019. Light starts to run faster , since engine is on. When the engine is off , light runs with normal speed. Thought it would be plug&play... But it seems not.
I dot think that voltage is problem, maybe impulse or some kind signal, because this thing only happen when you give some throttle ,and some time on idle works normal, then again doesent work normal ....What you could try is put a doide in series with the turn signal, voltage on the signal will drop by 0.7V
Maybe just enough to solve the issue.
Thanks for the quick response. I am sorry to hear you tried everything without success. At least I do not need to test it with different resistors. Because the problem is new to me, I am willing to try out some different actions, including texting Ducati and my Mechanical. If I will find a solution I will surely give you my feedback.
Can you tell me which battery voltage your machine shows on / off in the info menu?
Is the problem at front and rear turn-indicator in your case? At my Bike, that's the case.