Client not initializing correctly (looping ServerVerifyViewTarget)

We are having a problem in packaged build (development and Shipping), where the client initialization process gets stuck and Constuction/BeginPlay of some classes PlayerPawn, PlayerState and GameState are never called.

The MP logging on server looks like (simplified for readability, Full Version Here) :

RPC: BP_BattlePlayerController_C_1 - ClientVoiceHandshakeComplete
RPC: BP_BattlePlayerController_C_1 - ClientVoiceHandshakeComplete
Join succeeded: WartileGaming
[UActorChannel]  Owner: BP_BattlePlayerController_C_1. Reliable: 15.11 RPC: BP_BattlePlayerController_C_1 - ClientRetryClientRestart
[UActorChannel]  Owner: BP_BattlePlayerController_C_1. Reliable: 15.11 RPC: BP_BattlePlayerController_C_1 - ClientRetryClientRestart
[UActorChannel]  Owner: BP_BattlePlayerController_C_1. Reliable: 15.12 RPC: BP_BattlePlayerController_C_1 - ClientSetViewTarget
[UActorChannel]  Owner: BP_BattlePlayerController_C_1. Reliable: 15.12 RPC: BP_BattlePlayerController_C_1 - ClientSetViewTarget

And it will inter a loop where it will keep trying ClientSetViewTarget, just like the client (Full Client Log) :

ServerCheckClientPossessionReliable
ServerCheckClientPossessionReliable
ServerShortTimeout
ServerShortTimeout
ServerVerifyViewTarget
ServerVerifyViewTarget

It seems like the PlayerPawn is spawned correctly on the client, so it will never be able to VerifyViewTarget. But we don’t know why this is happening.