Thanks for providing the fixed project. I’ve run through the dedicated server setup project, and I’m not seeing the crash occur on my end.
I highly recommend using the guide I linked earlier, if you haven’t already. For 4.15, you’ll also need to remove the GetSupportedPlatforms function as well as the two that are commented out for 4.14 and later: A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums
I’ve tested it two times in the project you’ve provided, and the server is running as expected. As a result, we do not believe that this issue is a bug. If you find new steps that consistently reproduce the issue, feel free to leave a comment to reopen the thread and we can continue to investigate.
Have a great day