Hola Enzo!
Bug confirmed. Wow, this one is funny! 8) I have no idea of what is happening here, but it looks like a rare interaction with the real-time preview that I have to investigate. The steps can be simplified. You don't need an additional tool, just open R-T and select the preview. Very interesting, thank you for discovering this.
Mike, that warning message is shown by auto-diagnostics routines that can detect potential problems when a process is executed. Basically, these routines check that some basic properties of the processed image, such as geometry, color space and memory usage, agree with what the process promised to do to the image before execution. PixInsight is much more complex internally than what may seem from the surface
