As you might see in the miniature, there are two transistors and an arduino in this design:

Upon loading the design, one transistor is missing (1). And the arduino (2) is gone, too (including my luckily not so sophisticated sketch):

The right transistor (3) highlighted in white cannot be interacted with and stays even when creating a new design (to get rid of it CRUMB needs a restart):

Maybe my save could aid in debugging: