Hi, here ist the link to the .craft file: https://www.dropbox.com/s/pieqv6pogx852i8/KSS%20LAUNCHER2.craft The ship was build with an older Version of procedural Fairings. Then I remove procedural Fairings and installed the new Version. I noticed if I remove the old Interstage Fairing bases and add new ones the bug disappears so it seems something is saved weirdly with the old ones. EDIT: I forgot: This is Sandbox