Calling a Multicast RPC from a Player Controller creates a new Player Controller on the Client

Calling a Multicast RPC from a Player Controller creates a new Player Controller on the Client. In 4.7.6, this results in a repeating log warning: "LogPlayerController:Warning: Calling IsLocalController() while Player is NULL is undefined!" and occasionally: "LogNetPlayerMovement:Warning: CreateSavedMove: Hit limit of 96 saved moves (timing out or very bad ping?)". Note that in 4.9, the first warning does not occur, but the second does.

Reproduced in 4.7.6 and Main (//depot/UE4/Promotable-CL-2564509)

1. Create a new project
2. Create a Player Controller
3. Set the Player Controller as Default in the Game Mode
4. In the Event Graph, create a Custom Event
5. Set Custom Event to Multicast and Reliable
6. Call the Custom Event with a key input node
7. In the Construction Script, Self > Get Display Name > Print String
8. PIE
9. Note the log prints the Server and Client PlayerController display name once
10. Press the input key

Result:
The log reports another Print String as a separate PC is created on the Client, followed by a repeating log: "LogPlayerController:Warning: Calling IsLocalController() while Player is NULL is undefined!" and occasionally: "LogNetPlayerMovement:Warning: CreateSavedMove: Hit limit of 96 saved moves (timing out or very bad ping?)"

Note that in 4.9, the first warning does not occur, but the second does.