Small micro interruption on 912iS engine

What year is your engine?  It may well be one of the fuel pumps acting up.

I have heard reports of issues with bad pumps on engines made in the latter part of 2019 and all of 2020.

Thanks, the pumps were changed according the Rotax SB, perfect pressure. I always keep both pumps running during cruise. 

Have you checked the logs using the BUDS software?  What you are describing is too quickly transient to be fuel pressure, it almost has to be electrical.  If the BUDS log does not point to the problem I would start with the basics.  Check all spark plugs and plug boots, and make sure the boots are screwed into the wires firmly. Check the electrical connectors at the injectors.  I would also check that the lane A and B (round) connectors at the Rotax fuse box are secure with the collars fully latched. You want to make sure that the cables at these connectors are protected from vibration. 

Thanks! BUDS: i‘m not at my homebase right now, i‘ll download the file.

On my returnflight i found out, that with Lane B off, everything is normal, no power interruptions.