#component-lifecycle

A component with [Sync] fields added in OnStart (after NetworkSpawn) never replicates: each peer creates its own local instance and the sync pair silently never matches. The law covers engine components too: a Rigidbody built post-spawn is exactly this bug (Velocity is [Sync]-backed).

Update order is a property of the authored scene. A component added at runtime with Components.GetOrCreate goes on the end of the update list, no matter which GameObject it sits on. Per-frame input written from it lands too late for movement code that reads it the same frame. Drive the runtime component from an authored component's tick.

A scene-authored component cannot resolve, inside its own OnStart, a component that another component creates inside that other component's OnStart. Authored beside is not authored before, so the binder looks up the target before it exists, gets null, and holds that null for the whole session behind one warning line. The whole feature does nothing while every part it depends on works. Bind lazily instead: retry the lookup on a short interval until the target resolves, and warn once if it never does.