#sync

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).

A [Sync(SyncFlags.FromHost)] field on a runtime-created singleton never replicates: the object needs NetworkSpawn, not just NetworkMode.Snapshot.

Any cross-peer consumer (UI, host validators, scorers, range checks) that reads an owner-only simulation field gets frozen state on network proxies. Anchor off the replicated transform or redirect the field's getter.