Nodes are marked as missing even if they are present

Current Situation

When a job chain has file sinks they are marked as missing when they are referred to by another node with a yellow background color in the expert view.
Also in the graphical view they are marked as "missing"

Desired Behavior

Only nodes that are not defined in the job chain configuration and that are referred to by another node should be marked as "missing" with a yellow background color.