I have checked the code once again and couldn't find anything wrong. Apart from the possibility, that there is still a undiscovered bug in my code, the random knock problem could also be related to the LedWiz in combination with specific mainboards resp. chipsets.   Will try the following next: Experiment with somewhat longer delays between ledwiz update calls. If the extra delay doesn't help, I will need to add some code to record all ledwiz update calls with precise timestamps, so I can t