The issue occurs when running `valheim_server.x86_64` under `qemu-x86_64`, where the process hangs on a `futex` system call, resulting in an "Function not implemented" error.

Key points:
- The problem is specific to the QEMU emulator.
- It involves the `futex` system call not being implemented in the cross-compiling environment for ARM64 host using Ubuntu 5.2.0 version of QEMU.
- Replicated on an x86_64 Fedora host with a custom-built QEMU master branch.

This is classified as a **runtime** issue because it occurs during the execution (runtime) when interacting with the `futex` system call, which is not properly handled in the emulator environment.