thank you for this detailed insight. that is very helpful. and yes, this will most likely solve the "bug" I was encountering, starting the same timeline multiple times aka having multiple instances running.

ok, i had the compile error again. It is the timeline for sure. After moving a clip slightly, the project compiled successfully again. Therefore, it is not any asset or missing reference, the system which imports/transcribes/serializes the timelines fails sometimes.

i had some missing textures references in a USD file, coming from blender and RCpro complained with warnings. Since I fixed these warnings, I did not see any compile error so far. fingers crossed.