So, the Problem is the A/B Block. If i use an A/B Block in my Preset and i have a assignment on a Button for "Route to" Parameter.
The Preset goes crazy after i change some Parameter or effects in Path A. Sometimes i only have to change 1 parameter, sometimes i need to change more - this seems to be random, but the error will occure! After loading the Preset the Path A will be empty. If i load the Preset to times, the Path A is fully restored. If i change the A/B Block to an Y Block and Save the Preset - everthing ist fine. Maybe someone will test this.
For monosetups you can use the Y Block as an workaround.