Why don't clients see GameMode state changes?

GameMode exists only on the server. For shared multiplayer state (score, round timer, win condition), use GameState which replicates to all clients.

Subclass AGameStateBase. Add Replicated UPROPERTY for state. GetGameState() on client returns the live replicated copy.

PlayerState replicates per-player data (kills, score). Pair with GameState for global. Both auto-replicated by the framework.

Fix: GameMode Doesn't Replicate To Clients

Quick answer: Use GameState for shared state. GameMode is server-only by design.

Round timer in GameMode. Clients don’t see countdown. GameMode exists only on server.

The Fix

AGameStateBase subclass:
  UPROPERTY(Replicated)
  float RoundTimeRemaining = 300.f;

  virtual void GetLifetimeReplicatedProps(...)
    DOREPLIFETIME(AMyGameState, RoundTimeRemaining);

GameMode (server only):
  Tick: GetGameState<AMyGameState>()->RoundTimeRemaining -= dt;

Client:
  AGameStateBase* gs = GetWorld()->GetGameState();
  Read replicated value to update UI.

GameMode runs server-only. GameState replicates. Pattern: GameMode mutates, GameState carries.

Verifying

Two clients see same timer. Without GameState: only server-side counts down.

“GameMode server. GameState shared.”

Related Issues

For replication scope, see scope. For OnlineSubsystem session, see session.

GameMode private. GameState public.