The SceneCaptureComponent was correctly capturing the desired screen area within the editor, but as soon I ran my project in preview mode the created RT texture was mixed up. The image on the RT texture was blurred and different parts of the scene were shown, apparently related to their depth in the scene.
The only way I could fix that was by replacing the existing SceneCaptureComponent. Is anyone aware of this issues or are there any changes to the SceneCaptureComponent that have been made with the current UE version that I missed?